CA1188132A - Loading and transfer assembly for chemical analyzer - Google Patents

Abstract

Abstract of the Invention The present invention relates to an assembly and method for introducing and transporting sample containers in a chemical analyzer, and in particular, toan assembly for organizing randomly loaded sample containers in a positively-identifiable fashion. The assembly additionally includes a means for sequencingthe organization of sample containers and a novel means for dispensing measured amounts of sample therefrom.

Description

LOADIN~ ~ N~ TRANS~ER ~SSEM~I Y FOR C~I[~1IC~L ANALY~ER

Back~round of the Inve_tion T~liS application is a divisional applica-tion of: Canaclian Patent applica-tion 407,635, filed JLly 20, 1982.
13iological fiuids are routinely analyzed in hospital clinical laboratories to aid in -the dia~nosis of dlsease and to provide critical inforrnaLion about apatient s we~l bein~. The constituents oI blood Iyrnph urine or products derived therefrom provide meaningful inIormation to a clinician about his or her patien-t s health. With physicians becomin~ increasingly clependent on clinical laboratory data for the cliagnosis of disease and the rnonitorin~ of tl erapy automation has becolne essential to processing the increasing workload in hospi-tal clinical labora-tories. Automated chernical analysis of biological fluid cons-tituents has solved a great number of problerns associated with conducting reliable and efficient analysis; it has at the same time however has created its own dilemmas. Two lo~ical alternatives to autornation are either a much larger labora-tory staff or much more judicial selection of appropriate laboratory tes-ts by physicians. Since neitl)er of tllese solutions is practical however -the trencl is toward advanced automated che nical analyzers tllat rneet the neecls of the present day analyst. Although autornatic)n provicles a rneans by ~vhich an increased worl<loacl can be processed ral idly and reproclucibly lirr itations in the clesigll of autorr atecl instrulner ts make it cJifficult to achieve error free results of acceptable qucllity.

In clinical cl~emistry tl-le term autornation implies the perforrnance of arltllytic.ll tests throlJgl~ rnechanical or electronic control by an instrunrent witll only rninol ir~volvemr;rlt of an analyst. In the same conte~xt par-tial automation refers to proceclures in which the initial preparation of a specimen is done marlually bu t in which the analysis proceeds without hurnan in terven tion.

f` ~-Presently~ -the vast majority of chernical analyzers require considerahle marlipulatiol-ls by laboratory tecllnicians and thus fall into the latter catr ~,oryn Illustrative of these are tlle allocation of a patient's lluicl specilllel- ~or variou-types of analyses corlduct~cJ either manually or in various instruments;
appropriate dilution of specimen to meet the requirements of the various procedures; and complex book-keeping in order to keep ~rack of the disposition and concentratillg of the pa-tient's specimeil being analysed. On the o-ther hand, -totaJiy rnanual analysis i5 also performed for specific tests not amenable ~o au-tvmated proceduresg or wllere automated systems are either too expensive or cannot adequately be rnaintained. ~Since increased efficiency and reliability are necessary in the clinical laboratory, it i5 generally desirable to perforln as many s-teps as possible wi-thout this manual intervention. FuJI autornation reduces the possibility oi human errors that arise f rorn technicians making repetitive and boring rnanipula-tions, such as identifying, pipet-ting and analyzing a multitude of specirnens.

Reliability and reproducibility of automated analy-tical test resul-ts in a clinical chernistry laboratory are essential to maintaining the accuracy of rneaningf ul results to the clinician. Basically, the accuracy provided by automated chemical analyzers is no better than tha-t obtainecl by carefully conducted conventional techniques; however, the precision (repeatability) is greatly increased. Measurernent repeatability is of-ten poor when manual analysis is ernployed as a consequence of some bias introduced into -tne analysis by an indiviclual technolo~ist. Furtherrnore, -the ideal autornated analytical system should employ the rapidity ancl sirrlplicity of opercltion necessary for ernergency "stat" tests, small volurne specirnens requirecl for pedicltric pati~nts, and the high througl-put requirecl for routine analysis. ~\utornated equiplnerl that is properly clesigned of(ers greater reliability, less operative bias and more ra;)icl evaiuLltion of patient sarnples than is possible with marlu;ll metllods.
Whether analysis is performc~d manually, automatically or uses a cornbin-a tion of the two, tlle basic steps cornmol- to the analysis cycle are: sarnple entry into the instrurnent, sarnple distribution with or without subsequent 3~

washout of the sample probe reaction of sarnple with onc~ or rrlore reagents followed by a luar ti~ative deterlnination of sarl-ple pararrletrs arlcl dat a presentation. Major drawbacks oI currently used automated or partially autornated chernicai analyzers include the need of highly traincd Jaboratory personnel for the entry of sample and the operation of -the instrumer ts;
specirnen contarnination and variability of results due to carry-over from adjacent specirnens; a low throu~hput of sarnples to be analyzed; -the lack of versatility to conduc-t rnany ~ests on ~he same specirnen while retaining the capability of performing the same test on a multitude of different specirnens ina short period of time; and the absence of satisfac-tory back-up or control systems to conveniently ensure the veracity of test results; and lack of positive sarnple identification. The lack of positive sample identificatiorl in a clinical chemistry laboratory is crucial since the miscorrelation of tests results with apatient s specimeo can lead to incorrect diagnosis and consequently deprive the pa-tient of proper therapy. Extensive rnanipulation of a patient s specimen considerably increases the chances of incorrectly assigning the wrong test results to -that specirnen. Al-thougll several automated instrurnents have addressed -tlle problem of positive sample identification none have adequately solved it.
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1 leretofore autornatic cllemical analyzers have suffered from sorne or all of these problerns and thus have not provided the clinician with the reliability and versatility necessary for -the operation of mc)(lern clinicc labora tor ies.

Surr n1ary of the lnvent ion The present invention avoids the above-noted problems and drawbacks found with conventional cherrlical analyzers by providing a loaclin~ ancl transfer assermbly for presenting containers having fluid samples therein to a chemical analyzer which perforrns selected tests on the fluid sarnples. The assembly comprises a loading Ineans for retaining the sample contaillers that have been ranclorr)ly positionecl tllerein; a firs-t means associated with said loading mear for 3~2 seq~ellti.ally removinc~ said samp:le contairlers po~sil.i,olled thereir); a (-ransfer mealls for receiving said salllpl.e containers resno~ed from sai.d loading mealls; a means associated wil-ll said transfer means for idellti.fyi~ each sampl.e contailler received thereill; a rnealls a.ssc)ci.llf~l witl sa:id trans:Fer mealls for dlspeilsirlg at :Lenst a portion o~
the fluicl sample in each said sample corltalller into tlle chelllical analy~er; a seconcl mealls assocLated w.LI h said transfer mearls for sequentially removiny saicl sampLe containers received therein; a storage means cor receiving said sample containers removed frorn sa.i;d transEer means;
and a logic means for sequenci,ng the ope:ration of said loading, first removing, transfer, idelltifyi,llcJ, dispensing, second removillg and storage means in response to tlle operation of said cllemical analyzer and for posi.tively associatilly the test result ohtained with a particular fluid sarnple in the chelnical analy~er w.ith the identificati,on obtai.ned by said identifyirlg means from the sample container from which said ~luid sample was dispensed.

Desc:r ~ e Drclwlrlgs l;'icJ~re ]. is a top view of the preferre(] :Loa(]i.ncJ an~
tral~sE)ort asselllL~Ly of tlle presellt inveol-ion~
I'iglJre 2 is a L.op partia~. vi.ew of the loadillcJ
carousel hAVing a nu~ er of samE)le contai.llers l.oa(led tllereirl.
Figure 3 i.s a Eront elevated view, of a selni-].0 circular loacli.ng carousel mo-lrlted in tlle asseml:)ly in accordance wi L h one enlbodilllerll: of the E~resent inverltioll.
F'i.gure 4 is a top v.iew of the upL)er porl:ion of the transfer carousel in accordarlce with the presellt inventiorl.
t;'igure 5 is a top view, of the trallsfer carousel.
havirlg the upper portion removed therefroln.
F'igure 6 is a front view oE tlle meArls associated with the trarlsEer Caro-lSe]. for retai.ning contaillers in accordance with one embodiment of the present inventioll.

dm~ ., - 4a -~8~3~:
~ icl~lre 7 is a s:ide view of -the mealls asc;c)c.i.;lted w.i.~
t ~:larl~.Fc~r carousel for elevating the contai.ne:rs in one Iimerlt oE the presen-t invention.
Fi~ure 8 ls a side view of the means for Lowering t~le containe~s in one embodiment oE -the preserlt invention };igure .'3 i.s a sicle view oE the b(lr code se~ or, rol.ational means, and means associated with sai~ ~)ar code r FOI maintai.ning its fixed positiorl in accordance ~:itll one embodiment of the presen-t inventi.on.

Figure 10 ls a side view of the fluid level d(~tection system in accordance with one embodiment of the presen-t invention.
Figure 11 is a top view of the fluid level de-tection sy;t.ern oE the present invention.
E`igure 12 is a side view of the radiant energy er[l;tter assoc.ia-ted with the level detector system in accordance with one embodiment of the present invention t:a~en alonq lines 12-12.
E'igure 13 is a side view of the radiant energy sensor associated with -the level detector system of the present invention taken along l.ines 13-13.
E'igure 14 is a front elevational view oE a semi-circular storage carousel mounted in the assemhly in accordance with one embodiment of the present invention.
~ igure 15 is a side elevational view of the contai.ner receiving pOSitiOII and rela-ted apparatus of the t:rarl~fer assemhly in accordance with the present invention E'igur.e 16 is a front elevational view of the sample cli.s~)ellsor in acco:rdance with the present invention.

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I)eta~lecl nescription of the Preferre(l l~!nbodiment The loading and transfer assernbly of the present invention is a universal systern which can be adapted Ior use with any au-tornated chemical analyzer requiring acquisition oI sample for analysis. Of the three major types of automated chemical analyzers presen-tly available (the continuous-flow, discrete-sample and centriIugal force analyzers), the discrete-sample processing analyzer is preferred in accordance with the presen-t application.

A loadin~ and transIer assembly, in accordance wi th the presen t invention, is generally shown in Figure I at 10 to clepic-t the relationship between the assernbly and the chemical analyzer 1~. The assembly 10 first includes a loading means 14 for retainin~ a nun-lber of sample containers 16 -that have been randomly loaded therein by a laboratory technician or physician.
Prior to loading of the sample container in the loading means 14, no manipulation is required other than centrifugation of a patient s clotted blood to produce serum and the application of an identification label as described in detail below. The sample container loading means of the present invention is preIerably a rotating carousel 18 as shown in Figure 2 anci 3 having a substantially hollow inner core portion 20 large enough to house a mechanism 22 Ior displacing the sample containers therefrom. The peripheral portion 24 of ~the carousel has a plurality ~t radially extending slots 26 for receiving a number of conventional blood collection containers 16. The carousel 18 is rernovably mounted in the assembly and thus allows the analyst to loacl sample containers individually therein, prior to placing the carouscl in position. This collectiveloacling is advantageous to the analyst because it recluces the error associatedwi-th entry by decreasing the manipula-tion by the analyst.

~ n the most preferred embodiment of the present invention, the loading carousel 18 is constructed of two semi-circular carousel portions, each having twelve radially extending slots 21~ large enough to hold lour sample containers 16 each. The assembly lO thus has tlle capability of continually supplying sample containers to the instrurnent for analysis, since each semi-circular L3æ
onellt o~ the carousel l8 can be indiv:lduallytnounted or rellloved ~ c~llt i~terrupting the subsequent transfer proeess as :le<.cril:)c?d hereinafter. This allows the hospital cl:inieiarl t(, e~ficie}ltly eonduct analyses on numerous samples and to pr<)vicle tes-t results on a eontinuous basis.
In one ernbodiment of the present invention, as shown in E`igures 2 and 3, the loading earousel 18 is do~yh-nut-shaped, having a hollow inner core 2~ and a p~ripheral.
pc?rtion 24 eonstructed for receiving the sample eontainers~
The :inner eore 20 i9 large enough to house a sample eon-tainer displaeing mechanism generally shown a-t 22 whieh latera].ly displaees the sample containers Erom the radially extending slots 26. One sueh means Eo,r displaeing the sample containers from the loading carousel 18 ineludes a horizontal pushing carm 28 having a vertieal member 30 for a~,,utment against the containers and a horizontal member 32 eonneeted thereto which engages a mo,tor 34 to laterally disp:Laee -the horizontal member 32. Upon activation of the motor, the projections 35 in the horizontal 32 member are ei~gaged by a gear 36 thus transmitting a foree to the sample eontainers 16 and sequentially displaeing them from the carousel 16.
In the preferred embodiment of the present inven-ti.cn, the pushing arm 28 is operated under tension. The tension pushing arm 28 maintains the sample eontainers in a vf~rt:ical position at all times during displacement from tl~ carousel so that jamming of the eontainers between the lc~ncli.ng and trallsEer earousels is avoided. In aecordanee wil,h the present :invention, the pushing arm 23 is eonstruet-:3() ecl !~ }1 tilat lt is eapable oP disengag:ing the motor from tllehori,~,c)rlt~l member ~2 when the laterally d.lsplaeed eontainer ellcollnters resistance from the transfer earousel as deseri.bed in cletail below. Intermittent engagernent of the n~t~.r ~ h the hori.zontal member 32 insures th~l constarlt ~e~ ion reqlli.red to maintai.n the vertical positi.on of the c~lltainers, while at the same -time preventin~J the contain-er-: Erom beincJ bro]cen.
T}le radial.l.y extendi.ny slots 26 i.n the carousel :l~3 are equi.pped wi-th constricted segmerlts 3~3 or 3~ which enqage tlle outer walls of the sample containers and retain l~le containers in a fixed position. In this way, the c.,-lln~:Le containers are prevented from shifting position wil-hir) the slot 26, or falling out of the carousel 18 un-l~ss displaced during the normal operatlon oE the analyzer.
Conventional blood collection tuhes such as V~CI)TAINERS* (*Registered Trademark of, Becton-Dickinson) or specially constructed micro-containers can be used in accordance with the present invention as further described be]ow.
The transfer means of -the present invention generally shown at 40, is a crucial component of the entire assembly and functions as a mediator between the loading of salnp:l.es into the chemical analyzer, the identifica-tion of samples and consequent recognition of tests to be preformed, dispensing of samples from the containers ancl iinally dis-pensing of the smaple containers from the transfer means ~ to a storage means retaining them in an organized and po~-;itive:ly identified manner. The preferred transfer means, :in accordance wi.th the present invention, is a rotating carouse]. 42 having an upper portion 43 with a plurality oE
se~icircu.l,lr slots ~4 circumscrihed around i-ts periphery Eor roceivirlg ànd re-taining samples from the ].oading carousel .3() 1.~ he size and shape of the slots 44 coincide generally will-~ t}le dimensions o~ the sample container to be placecl therein. The loading 1~3 and transfer 42 carousels are preferabl.y positioned adjacent to each o-ther such -that direct ]h,/ -~3-t! ~ mple containers 16 from the~ loa(lirlc3 carousel ~ is facilitated ancl cumbersome conveyor assembl:i.ec; can 1~? ~.Lirninated. PreEerably, the loading an~l t.ransFer c.-lrollsels are mounted for rotation about their resE~ective a.Yc~ in opposite directions. In one embodi.ment of the ~resent invention, the loading carousel 18 is mounted for cc)llrlter clockw.ise rotation and the transfer carousel ~2 .i.; rnounted for c:Lockwise rotation~
rl'he transfer earousel 42 ineludes many Eeatures wllicl-l assi.s-t in the iclenti.fieation and dispensing of sample from the containers, said features capable o:E
being used alone or in eombination with each o-ther as describe~. herei.n. Many of these features are amenable to variatiorls in struetural design, and therefore are des-crihed herein as the preferred embodiments in accordancc?
with the presen-t invention.
~ s shown in Fiyures 5 and 15 the first component ot. the transfer earousel ineludes a means 46 for prevent-incT the harsh (non-gen-tle) transfer of the sample eontain-~0 er~, into the earousel 42. As the containers are displacedfrom the loadlng carousel 18, the top portion of the container 17 is generally at a position behind the bottom portic>n as the eontainer enters the trans~er slot 44 a.ssociated with the eontainer exehange position S0. ~s the bottom portion 19 of the eontainer meets resis-tanee from th~-? transfer earousel, the upper portion 17 snaps into posit;.on against the upper portion 43 of the earousel, re-sl.lLtlng in sp.illagc? of fluid and craeking of glass eontainers.
~n anti-splash 46 clevice prevents sample Erom splashing 30 C?llt o;E the eontainers as they are transferred into the l-.r,lns~er carousel 42, and will also prevent cracking of glass containers. The anti-splash device 46 of the present :i.nvention is preferably a spring-tension arm 48 ~hi ch iS

i .;~ lb/

~1~'B'132 o~liqllely mounted on the bottom of the caronst7l 42 as ~ ow~ igure 15. Disposed at the top L~ortion oF the .~-mll 48 is a contact mernber 49 positioned to con-tact the colltainers cluring exchange. The spring-terlsion arm c~sl~ions the entry of the upper portion of the contalner .~1'. i t i s tran~; Eerrt3d .
The second component of the transfer carousel 42 is a means for randomly introducing sample con-tainers into the ~ssemb]y 10 forward of the pre-loaded containers. This usllally occurs when a patient's specimen must be analyzed on emergency basis, and is generally known as a "stat"
situation. In accordance with the present invention, the -transEer carousel 42 is equipped with a means for randomly introducing eme-gency or "stat" specimens forward of Ihe pre-loaded containers while maintaining the original position of those containers in -the assembly. There are two "stat" loading positions in accordance with the pre~
sent invention. The first "s-tat" loading position 48 is generally shown in Figure 5 as including sample container re7taining slots I, J, K, Lj and M. These "stat" loading positions precede the fixed sample exchange slo-t position 50 (N) in the clockwise rotational cycle of -the carousel.
Introduction .i I q~3 lb/ ~

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I t~
of stat samples into these carousel positions insules the rrlainterlance of tllcpre-loacled sarnple container p ositions in botl the loacling 1~ ancl transler 42 carousels.

The second stat loadin~g position 52 (O) is locate l iml-necJiately forward of saicl exchange position SO and directly rearwarcl of a sample iJentifyinK
rneans 54 llaving tube in position (A). Unless this stat loading position (O) isempty a pre-loaded contairler must be removed from the assembly before the stat specimen is introduced. Since both lstat loading positions precede the iden-tifying rneans 54 in the ro~ational cycle of the assernbly randorn loading of the stat specimens is facilitated and the positive sarnple identifica~ion feature of the present invention is not precluded.

A signalin~ means 56 is associated with the transfer carousel and is preferably Jocated adjacent to the second stat position 52. The signaling means varns the analyst when the carousel 42 is ready to advance a step in its rotational cycle. Thus when the analys-t is required to loacl one or more stat samples into tlle transfer carousel he or she is provided with a rneans for doing so safely. A pair of light-emitting diodes 5S are associated with the si~nalin~
means 5~ as indicators of the rotational status oI the carousel 42. Illustrativcof -this is the stand-by mode wilereir one of the li~l-t-emittin~ diodes illuminates a red color and the rotational mode wherein the other diode illurninates a ~reen color. The clinician can safely place a sarnl le container in the stat position at 52 (O) of tl e transfer carousel only in the stand-by mode.
The third con ponent of -the transfer carousel 42 is a rneans Ior positively identifying sample contail-ers in the carousel and for obtainin~ specific instructions for the chemical analysis of the sample within -the assernbly of the present invention such that -the Jocation of sample container is positively iden-tified. Up to this point the patients specimen has been randomly loaded withill the analyser assembly 10 and has thus required no error-prone and time-consuming recorcl keeping procedures. This is a major advantage of the present invention over the prior art since it eliminates sources of error saves precious 1~88~32 ~ illle allCl al.l.owg ~ile c:lin:Lc:iall to conduct signiFic.lntly In-~l`t! arlal.~.es thcln he or slle could do otller-,1Lse.
~ s s}lown l.n Figllre 9 and 1.0, t}~e containe~
:i.~.lelltiFying means utilizes a bar code label 60 horizonta].ly po.it:ionetl oll t:he lower portion 19 oE the sarnæle container h, t.he cl.in.ician alld a bar eode sensor 6~ loc~lted adjacellt.
tlle~:eto ~Eor. sensing the coded label. ~rhe bar code sensor ~;:? is a eonverlt.ional refleetancQ-type racl:Lant ~nercJy dovice~
caEnlble o.t re~cling bar eodes. It ls preferred that the 0 her code sensor 62 remain stationary and that the sample cc-r)ta:iner 16 be movable sueh -that the entire code can be scrl-.ed. There:Fore, the eontainer is rotated about its ~e:rt:ical axis i.n Eront of the sensor ~62 duriny reading of Ille bar code 60. A common oecurrence in clinical labor-al-ories, however, is the s~illage of sample specimen alony the side of the eontainer or the placement of thumbprints on the sample container during handling. This can destroy a porti.on of the bar code 60 and ean result in an inaceurate sensing o~ the bar eode unless a broadened field of view is available to the sensor 62. In aecordance wi-th the p.resent invention, the eontainer is elevated as well as ~otated during the xeading of the bar code to permit the sensor to detect several regions of the code in a spiral rashiorl. Preferably, the sample container is rotated so as to make three revolutions about its vertieal axis during th.is procedure.
The rotation of the sample eontainer during sensing oE the blnary code 60 ean be easily aeeomplished in a vari.et:y of ways. In aeeordanee with the present inventiorl, the rotation of the eontainer is aeeomplished by the re~er-sible engagement of a hori~ontally mounted clutch or rotatinq whc-el. 80 with the edge of the container as shown in Figure 9 Cirumscribed about the edge of the wheel 80 is a resilient I i)/ -11-3~
b~ .tr ~,) m~lde of rubber or the like for cushionirlq the c,~ act he~-ween the wlleel 80 and the container 16. The r~ lt:irlc~ w~lel 80 is rnollnted adjacent to the t:rans.fer cllt-ousel ~12 at: a posLti.on coinciding with the sarnple id~ ific,ltion posit.ion generally indicated at ~ and i~ld:icated by ]e~tter A in Figure S. 'Phe reversihle engage nl.~llt of tlle rotat:lng wheel. 60 with the conta:iner is controllecl by the logic means of the analyzer.
Since the diameter of the sarnple contai.ners varies from container to container, and some con-tainers have irregular surfaces, rotation thereof during sensing of the bar code 60 can cause an error in the reflec-tance-measuremen-t. The absolute requirement for error-free sensing oE the bar code dictates -that the focal length hetween the sensor 62 and the surface of the container reTnain cons~an-t. Consequently, -the distance 6~ between ~he bar code label 60 and the front edge 66 of the bar code sensor must not change in response to variations .in c~ntainer diameter or eccentric (out-of-phase) rotaLiorl.
In accordance with the present invention, the -transfer carousel 42 is-equipped with a means for main-taining the sensor 62 at a fixed distance from the surt~ace of the sample container during rotation. One such means is shown in Figure 9 and is illustrative of the type of mechanism which can be used in the present invention. The hori~ontally positioned sensor 62 is passed through an opening 67 in the vertical leg portion 63 of an L-shaped coupling member 65, and is securely coupled therethrough.. The vertical leg 63 extends down-wardly from the opening 67 and is connected to the top portion of a pair of spaced-apart vertical metal bar members 70 and 72 which are securecl to each other at both ends by conventional nut and bolt 78 arrangements.

Lb/ -l2-~8~32 ~ hori20nt:al leg port:Lon 76 oF the L-sl~aped couplincJ
member 6~ ha~ a small rotatable wheel ~:L corlllected thereon.
'I'lle wheel ~1 is mounted on -the base 74 throu~h the vertical bars in a position to constantly engage an edge ol- the container during rotation, such that the distancc ~ between the Eront edge 66 of the sensor ancl the edge of t}-e container remal.ns fixed. For example, if the diameter of the containers varies from one to anokher, or if -the surface of A single container is irregular causing eccentric ~out-of-phase) rotation, the sensor 62 is capable of maintaining its required degree of accur acy .
Although the sensor 62 can be~ connected to several difEerent mechanisms as that described above for maintaining the fixed distance 64, we have found t}-~is embodiment provides an additional measure of accuracy in the bar code sensing procedure. As -the sensor 62 is displaced lateraIly as shown by the arrows in Figure 9, the upper portion of the spaced-apart vertical bars 70 and 72 traverses an are as illustrated by the phantom lines. Consequently, the sensor 62 would have a ten-dency to be deflected upwardly out of its horizontal plane causing the light beam (not shown) to be deflected away from -the bar code label 60. In accordance with the present invention, we have found that the bar code sensor 62 remains substantially perpendicular to the surface of the sample container at all times, and the li~h-t beam is not displaced vertically as the vertical bar rrlernbers 70 and 72 are laterally displaced.
A significant contribution to the design of automated analytical analyzers in accordance with the present invention is that two or more types of sample containers can be employed. A first type of sample container is a conventional blood collection tube as . .
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sc:r.ibecl atiove for coll.ect:lng blood sam~les from a -a~i nt. Tlle second type oE sampl.e container, ~/h:ich Ims beerl spec:ifically designed to hol.d small quantitic?s oE liquid .is the subject of our copending Canadian a~pl.icati.on Ei.].ed July 20, 198~, Serial No. ~07,611, a~ a~; all elongclted cyclind.rical housing oE thc same ~eneral shape as the conventional blood collection tU~ff 1~ut has. tlle sampl.e holcling compartment having smalLcr di.mensions clisposed at the top thereoE. These micro-:L0 _ontainers are easily handlrd by a laboratory technician,resllltirlg in a rapid and reliable processing oE fluid specimens Eor ana].ysis.
S.ince the general dimensions bverall of the miero-container are similar to t.he s andard samp7e collr~ction tube -the clinician is able to conveniently grasp -the mi.cro-container by its elongated housing portion as he or she would a conventionai container. This facilitates overall processing of the fluid samples since a clinician routinely handles a large ~umber of tubes in a single day, and thus his eff1cieDt operation is not hampered by the manipula-tion of small, odd sized containers. The elongated housing also provides an adequate area for posi-tioniny of labels or other means of identiEication on the container to facilitate positive sample identification in an automated clinical analyzer. In addition, the elorlgated cylindrical housing acts as a permanent support ~Eor the mic:ro-container such tha-t tipping of the container arld subsequent spillage of precious sarnple is avoided.

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-13~-i~ npot tant featurc oL thc loacling arlcl transler rls5e1nbly of the yrcse1)t invt~ iol-1 is its cal~;1bility of introc1ucing a patient's spcchnorl h~to thc analy~.er fro1n various si;~ec1 containers. /~ ough the micro-contliners dcscribcd aboYe e.~ s;ly be p1aced in the assernbly, it is preierred to di~ti1~guish bct~eerl the mi~ 1o-~ o1ltainers a1-d con~entional containers for dis1~n.ing oE tllc sample t1~erel1o1n in orcler to avoid d;lrnage to t11e dispenser arld to precisely position the (lisl~cnser clurin~ aspiration. T1-ol c~ore, the asse1nbly of 1he prcsent invel11iol1 includes a rneans of distinguislling between the -two types of contc1in~rs in the trans~er carousel 42. Furtherr1-lorc, the contai1ler 0 c1isth~g1lishin~ means can also be used in conjunction with -the bar code sensor to tleter1ni1le the presence or absence of a container in -the id~nti~ication positio1l 84 of the -transfcr carousel 42.

The i lentifying means in the preferred embodiment of the present invention includes a transmissive light source 86 and detector assernbly 8~ as sho~n in Figure 10. The conventional liglIt source 86 is a ligllt-emitting diodeWhiC~I horizontally passes a bearn of light through the sample contair-er 16 to a Jight-detecting diode in the detector 88, unless the beam is blocked by the presence of a non-transparent labe~ 90 or ather indicia on -the sample container~
If no label 90 is detected during rotation of the con-tainer, the sample container

2 o is pr ocessed by the assembly as a micro-container. If a label 90 is detected, the presence of a conventional is confirmed. In order to establish whether or not a srnall volume container is truly present, a bar code 60 rnust be sensed as described above. If no label 90 or bar code 60 is sensed, the absence of any cor1tai1ler in the transfer carousel 42 is confirmed and entered into the microprocessor assembly.
.
The elevation of the sample container during sensing o~ the bar code 60~
as shown in Figure 7 is accomplished by a conventional worm drive 92 connected to a gear and operated by a motor 93. A vertically moving nut 94 is freely mounted around the worm drive 92 as sllown. Actuation of a motor

3 o causes rotation of the worm drive 92 with subsequent upward vertical movemel-t of the nut 94. An ed~e portion 96 of the nut is positioned to enga~e ' , . . .

3æ

th~ bottom portio n of a sample container support 98 member as sl-ow n in l~i~ure 7. This causes the elevation of said support mernber 9~ wi th consequen t eevation oI the container 16. The elevation means is furLher ernploye i as part ci a level-sensin~ device for accurately sensin~ the level of liquid sarnple in the or tainers. The level-sensing means and associatc I dispensirlK mear-s are dscussed in detail below.

Autornated chemical analyzers employ various sarnple-dispensing mean Jepending on the nature of the analysis system and the number of tests which ^an he conducted. These sample-dispensing arrangernents have been devised to maxirnize the speed at which samples can be dispensed and to mimimize contamination due to carry-over from adjacent samples. In accordance with the present invention a means for dispensing the sample has been devised which is rapid reproducible and which eliminates sample carry-over. The main components of this system are a level-sensing means generally indicated at 110 in Figures 10-13s and a means associated with the dispensing mechanism for successively extracting sample from the containers in response to the liquid level therejn. An additional advantage of the sample-dispensing means of the present ir vention is that sample specimens of different volumes can be analyze~ without replacing the sample aspirator or predilution with reagents or diluents The sample dispensing means of the present invention operates in a manner that advantagously permits the clinician to load specimens containers having different liquid volumes into the analyzer. The level-sensing means utilizes ~he worm drive container elevation system shown in Figure 7 previously described to elevate the sample container.

Basically the sample container is vertically raised until the meniscus of the liquid in the container reaches a predetermined level wherein the radiant energy Irom a radiant energy source 112 is reflected from the surface of the /liquid t(l a radiant energy detector 114. The radiant energy emitter ~6-and detector 114 are positioned relative to each other and to the sample container locationsuch that the detector 114 will receive the reflected radiant energy at a threshhvld value only when the meniscus reaches a predetermined level. Once 38~32 ~:hi;~ e(l~t~rln:irle(3 leve]. h~s been reached, the vert:ical d:i.pl.acem~llt oF the sample contai.ner is stopE)e~, and the sampl.e container :is subsequently rnaintained in the elevated position for furthe.r analys:is.
In accordance with the preferred embodiment of thr~ l~leserlt -illven-t:ion, the elevation ma:irltzlinillcJ rneans gellerally shown at 130 in ~igures 6 and 8 includes a pair of spaced apart vertical posts 132 and 134 mounted on the base oE the transfer carouse.~ 42. A horizontal base 98 for supporting the containers 16 is secured to the vertical posts 132 and 134 at its opposite end portions and is vert:lcally movable at its opposite end portions and is vertically movable along the posts. Ad-jacent to and preferably connected to the hGrizontal base support 98 :is a movable friction member 136 which is engayeable with -the base member 98 such that the friction member 136 will retain the base member 98 in an elevated position at any height along the vertical posts 132 and 134. Pre-ferably the friction member 136a and 136b is constructed of two half-cylindrical sleeve members which are clamped -I:orJethe~ around the post 132 by a spring.
After dispensing of at least a portion of the sample from the container, the transfer carousel 42 can be rotated to a position such that the horizontal base memt)er 9~ ensages to a worm drive assembly lgO having the same gelleral contruction as the elevation assembly. The onl.y clifEerence being that the nut 142 is po.sitioned above the support member 98 such that the rotatlonal movement of the worm drive 140 by motor 144 transmi-ts a downwarcl move-30 met) t to the sample container to be removed from the transfercaro~lsel at the same height that it was loaded.
In the preferred embodiment of the present invention, the radiant energy emitter 112 and radiant energy detector ..~.;

1 1~ .12-t` r~oC il-.ioned on substant:LRI~y op~o-;i.t( si.cles of a v(~rl:ical plalle de~ :Lnq the vertical ax:is Or the sample c(:~ ;nerr and ~Eurther positiorled such that the em.Lssion n~ rcldi.allt energy is detected through reElectance Erom ~l~e ai.r Fln:icl surface of the samp:Le on the container olll~ wllen ~he meni.scus reaches a predeter~in~(l ].ev~
~ 5 showrl in Figures 10 and 13 tha racli.allt: ~nergy detector .L1~ compr:Lses a bifurca~ed housing l:l6 having a fi.rst housin~ member 118 aligned with the emitter 11~ an~
.I second housing member 120 extending on opposite sldes oE
the .Eirst member l:l8; a means for sensing detected energy in each branch of the second member; and an energy-directing means positioned at the branch pointof said housing to reElecL radiant energy passing through the first housing l.l8 member to the energy sensors of the second member 120.
The energy--directirlg means is preferably a bifrontal surface 122 such as a polished mirror which will deflect the radiant energy to either branch 124 or }25 of the detector housing.
While a T-shaped bifurcated housing will suffice in accordance with the present invention, a Y-shaped housing is pre~erable An equivalent detector cor~prises a pair photo cells positioned adjacent to each other detect the reflected energy, said photo cells being positioned in close proximity to each other.
In accordance with the presen-t inven tion i5 prefer-able to use infrared radiation as the radiant ener~y source however any radiation source capable of transmitting through l:he p]astic or glass containers is suitable.
The transfer carousel of the preferred embodiment of -the present i.nvention further includes a container removing melns as described hereinabove for the loading carousel, wh:ich removes the sample containers from the transfer carousel to a storage means for receiving the identified sample contairlers and retaining these sample con-tainers in an orrJani~ed manner.

z ~ e cLoracJe meell-s o.E the presel-t invent:ion is preF-<?ral:-.Ly a rotatincJ carousel lO0 as shown in Figure 14 having a slll>~-~tallt:ia:ll.y ho:l:l.ow lnner core portl.on 102. ~rlle peripheral .~ortion 10~ o.E the carousel 100 has a plurality of radially ex~ellding sl.ots (not shown) for receiving a number of conven-~:ion.ll blood collection contai.ners 16 as described Eor -the loadiny carousel. The carousel 100 can be removabl.y moun.ted in the assembly and thus allow the analyst -to remove the posit:ively :indentiEied for storaye in a cold room or reErigerator. This col.Lective stori.ng capability is advantageous to the analyst because it recluces the error associated with the storage and trallsfer of individual containers. In the most preferred embodi.ment of the presen-t invention, the storage carousel 100 is. constrllcted of two semi-circular carousel portions, each portion having twelve radially extending slots large enough to hold four sample containers each. The clinician thus has -the capability of removing from the instrument wi-thout inter-rupting the processing therein. This allows -the hospital cl:inician to efficiently conduct analyses on numerous samples and to provide test results on a continuous basis. In a preferred embodiment, the storage carousel 100 is interchageable witn the loading carousel 18 such that an empty storage carousel can be used immediately for collectively loading sample containers into the assembly :L0.
Moun-ted on the interior 102 of the rotating storage carousel 100 is a means for indicating when the slot is full of containers. In the preferred embodiment, this is a sensor such as a microsw:itch 106 located adjacent the peripheral portion 104, which is activated as the sample containers are completely loaded in the radially extending sLots as shown in Figure l.4. ~s the last container is unloaded from the transfer carousel 42, an act~ating arm 107 is forced against a switch pin 108 and completes a circuit in the switching assembly 106 - ~.8 -PClb/

~L88~
e activation causes the rotation of the stor~ge carousel and posi,tions an open slot in.Eront of the e~challge pos,ition ).09(~l) of the transfer carousel 42 for ;Eurther un:Loacling.
The storage carousel lO0 fur-ther includes a mearls ~or loca-ting sample containers and correlating this loca-tion with the ~ositive identity of the sample container through a microprocessor after they have been removed from the~
transfer carousel 42. This .Eaci:Litates the rap:id locati.on of sample and pro~ides a backup system Eor -the chemical ana.Lyzer.

For example, if.an analysis of sample is inadequate or erroneous, or i:E the amount of a sample .constituent is off-scale, the locating means oE the storage carousel can be used to conven-iently retrieve the sample f'or reloading in the loading carousel without further m~nipulation as ir ccnventional analyæers. In conventional analyzers, any sample which mus-t be repeated for the reasons discussed above ~ust be reprocessed in order to obtain reliable test resul-ts. rrhe preferred locating means associated with the storage carousel is a binary code lll located on the bottom of the carousel which can be read by a binary code sensor.

--1 a A--pab/, 3~
.I'rc~erred Operatioll of the Inventioll ~ rhe ove.ral]. operation of the loa~ing and transfer assembly of the present invention i8 sequenced by a micro-processor syst:em which delivers speciflc instxuctions to the v;-lr.ious operat:ing components of the assembly in response to the r-eecls o:F the analyæer. These lnstructiorls co~reo,pond to speciflc test requests entered into the mlcro-processor te~m.l.ll7ll.
at the time a patient's sample ls entered :Lnto the assembly.
by tlle analyst. Because the sample containers can be randomly loacled and positively identified in the assembly of the present invention, the test results are readily assoc:iated with the correct patient specimen with a minimum of -the the analyst's effort. Considerable time-consuming record-keeping tasks are significantly reduced, and errors in the reporting of test resu].ts is almost totally eliminated.
In a preferred embodiment of the present invention, a patient's blood or other biological fluid would be collected in accordance with a physician's instructions. If a blood sample is drawn from a patient, the phlebotomlst draws the ~lood in-to a conventional blood collection tube or a specially designed micro-con-tainer as described in our co-pendin~ Canadian application entitled'~ontainer for Small Quantities of Liquids" Serial No. 407,611, filed July 20, l9F32. The phlebotomist then enters -the patient's demographics and physician's test requests into the microprocessor which generates a test list and identification corresponding to a bar code label and places -the label on the blood collec-tion tube. Hereinafter, no signiEicant further manipulation or record-keeping is necessary before loadiny the specimen into the clinical analyzer.
Under normal circumstances, the coded specimen container is randomly loaded into a semi-circular carousel together with as may an 47 other containers. Two o~ these ~ab/

~88~3~

se~ circuLar assemblies 1~, rnounted on the assembly by the nr~ Lyst, :rotate counterclockwise as they sequent:ially intro-d~lce sample con-tainers into -the exchange-slot position 46 o:E the transfer carousel 42. If the transfer carousel 42 is cmpty or only partially loaded with con-tai.n~rs, the analyst may pLace the samp:Le container directly thereirl. In an pah/

- ~o -emergency or "sta-t" situatiQn a patiellt's sp~cilnen container is conveniently randolllly loadeci into orle of several "stat" loaclin~ positiol s oJ tllc clocl<wise rotating transfer carousel at a position ahead of the preloaclecJ contai )ers i n th~
assembly. There are essentially two types of "stat" loacling positions in the preferrecl ernbodirnent of the present invention.

Tlle first type of "stat" loading position 48 consists of the contairlcr receiving slots loca-ted rearward of the container exchange slot position 46 which couF)les the loading and transfer carousel and forward of the container-exchange slot position which couples the transfer and storage carousels 109.
Utilization of these "stat" loading posi-tions permits the analyst to loacl con-tainers into the assembly while maintaining the pre-loacled posi tion of previously loaded containers in the entire assembly. Thus the analys-t does not have to remove any containers from the assembly prior to entering a patient's sampie into the -type of "stat" loading position.

The second type of "stat" loadin~ postion consists of a single container-receiving slot position 52 whicil is located forward of the con-tairler-exchangeposi-tion 46 in tlle transfer assernbly. Unless this slot position 52 is empty acon-tainer must be rernoved by the analyst prior to loading the "stat" sample container. In accordance with the present invention sarnple containers are randomly loacied into either the first 48 or second 52 type of "sLa-t" positionssince the means for positively identifying the con-tainers 5li is positioned forward of both "stat" loading stations. This is a considerably advantage to theanalyst since it elirninates the additional record-keeping associa~ed with this -type of exci-ange and a considerable advantage to clinical analy~ers in generalsince it reduces the chance oI erroneously identifying the "s-ta-t" specimen.

During normal operatio - the transfer carousel 42 rotates clockwise through a number of stations for performing operations on the patient's specimen. The tirne that a sample contairler remains in any one posi-tion in therotational cycle oi the carousel depends upon the nunlber of analy-tical tests requested by tlle physician ~or that specimen and is con trolled by tlle rnicroyrocessor. Tlle minirnum rest tirne for a contilir1er in ar)y on( posilion is 10 s~orlds, since the Inicroprocessor is either prograrrlrnc(l t(~ aclv.lr1c(- tl~e caro~lsel once d~ring this interval, or cvrl-tains instructior1s ~or only one tcst to be cDrldllctecl on t~le specimen. On the olller hancl, at a ra~e of 5 se-or1ds pcr -testrequest, tl1e rest tirne can be as great as 165 seconcls if 32 analytical tes-ts are reques tecl.

Irl accorclance with the present irlverltion7 tlle microprvcessor sequcnces t~ese various opera tions in the transfer carouseJ 42 in a rr1ore reliable and 5gr~ificar1tly rl1ore rapid manner than presently available autom.-lted clinicalInalyzers. Once the sample container is removed from the loadin~ carouse3 18~
i t is transpor-~ed to the container-identifyin~ loca tion 54 whicll positively identiIies -the sample container and correlates it with the test re~uests entered by -~he anaJys-t into the rnicroprocessor. This is clone by reacling a bar code 60 placed on -the container 16 by the phlebotor-nist. At abou-t -the sarne -time, -the transmissive~ ht source assembly 86 and 88 determines the presence or absence of a label 90 or Gther non-transparent portion on the sarrlple containerin orcler to distin~uish between the conventional blood collection tubes and themicro-con-tainers. In accordance with one embodirrlent the preser-~t inventiorl, it is necessary for tile nr.icroprocessor to know the type ol the corltairler, since the sample is dispensed from ttle cootairlers at two ditfererlt rates depending upon the cross-sectional area of the container lloldirl~ tne fluid.

The bar cocle 60 is read by a stationary binary code sensor fi2 positioned adjacent -to a sample container, wJ-licll is positioned for rotation about its vertical axis. Dllrirlg sensirlg oI the bar code, the container is also elevatedsuch that -the sensor senses the bar code along a spiral path to insure that no information is deleted. At about the sarne time, the transrnissive~ ht source assernbly 86 and 88 cleterrnines Ihe presence or absence Or a label 90 Gn the container or housing o~ tile micro-container.

Once -the sarnple contairler has bc-en positively iden-tiIied, the type ol container deterrnilled) and the presence of a container confirmed~ the assernbly 3~

can clispense portiolls of the sample into the curvettes associ. ted witn ~hc chernical arlalyzer. The iirst step is to elevate tl)e con~ainer ~o a llcight tha~
coincicies with a predetermirled lleigllt of the sample clispenser probe 1'~6. In accordance with the present invention, the sampJe con tainer is elevate(i by a worm drive assernbly 92 and 94 until the rneniscus of the fluicl level is sensed by a level-serlsirlg rneans such that precise sarnpling can be acllieved by the dispensirlg means. If the dispensing means is not located at the elevating positio~ he corlt.liner is rnaintained in -the elevated position as the transrercarousel is ro-tatecl to the location of the dispensing means.

In accordance Witll the present invention, a fluid-sclmple dispensing probe 146 rotates to a position over the sarnple contairler~ descends to the predeterrnined level where the lower portion of the probeis tip 148 intersects Witil -the liquid surface, and aspirates sample tllerefrom. 13uring aspiration of -the sample, the probe tip 148 descends at a fixed rate depending upon the size of the container, such that the tip 148 of the probe 146 coincides with the meniscus level 150 of the fluid at all tirnes. After transfer of the aspirated sample ~o a chemical analyzer, the probe returns to aspira-te nnore sample if requirecl, and descends to a new fluid level 152. The descent of the dispensor to the new fluid level and the rate of descerlt during aspira-tion are botll controlled by the microprocessor.

With sarnpling completed, -the transfer carousel ro-tates -the sample container to a container lowering position which consists oI a worrn drive assembly 140 and 142. The lowering(the container to its original height ocurrs beIore it is removed from the transfer carousel to -the storage carousel 100.
The container-excllange slot at position 109 associated with the storage carousel is equipped wi-th a microswitch 106 which activates the rota-tional cycle of the stora~e carousel 100 when the slot is completely filled with samplecontainers. Wilerl actuated, the carousel rotates counterclockwise to make a new position available for unloading containers frorn the transfer carousel.

The storage carousel 100 is equipped with a binary code sensing systern 111 Eor positively identilying the position of the sarnple corl7ainers in the storage carousel. Unlike the loading carousel 1~ wl ich cont.~ ecl rardomly loaded contailers ti-e storage carousel IOU carries tl)e sa rll)le contairlers ir a hi~hly or~ani~ed manr er. As the containers are urllo.l(Jed frorn tlle trallsfc~r carousel to the storage carousel the binary code 111 associate~cl witl~ the slotposition containil-~g the unloaded container and the carousel nurr)ber is sense J by the binary code sensor 112 assembly and the binary code number is printed out for the analyst ~vhith the positively identified test results. The analyst can tt en retrieve tl e patierlt s .spPcilrlen from a nurrlber a storage carousels simply by referring to tlle binary code number at the test result sheet.

Although the present invention has been described in terms of its preferred embodill~ents and specific features have been set forth; it will be obvious to one having ordinary skilled in the art to make modifica-~ions and substitu-tions thereof without departing from the spirit and scope of the invention.

Claims (41)

What is claimed is:

1. a loading and transfer assembly for presenting containers having fluid samples therein to a chemical analyzer which performs selected tests on the fluid samples, said assembly comprising:
a loading means for retaining the sample containers that have been randomly positioned therein;

a first means associated with said loading means for sequentially removing said sample containers positioned therein;
a transfer means for receiving said sample containers removed from said loading means;
a means associated with said transfer means for identifying each sample container received therein;
a further means associated with said transfer means for dispensing at least a portion of the fluid sample in each said sample container into the chemical analyzer;
a second means associated with said transfer means for sequentially removing said sample containers received therein;
a storage means for receiving said sample containers removed from said transfer means; and a logic means for sequencing the operation of said loading first ?moving, transfer, identifying, dispensing, second removing and storage eans in response to the operation of said chemical analyzer and for sitively associating the test result obtained with a particular fluid mple in the chemical analyzer with the identification obtained by said identifying means form the sample container from which said fluid sample was dispensed.

2. The loading and transfer assembly of Claim 1 wherein said storage means further comprises a means for retaining said sample containers in an organized manner and said logic means further comprises a means for identifying the location of said individual sample containers organized in said storage means.

3. The loading and transfer assembly of Claim 1 further comprising a means for collectively loading the randomly positioned containers in the assembly and for collectively storing said positively identified containers removed therefrom.

4. The loading and transfer assembly of Claim 2 further comprising:
a means associated with said loading means for collectively loading the randomly positioned containers in the assembly;
a means associated with said storage means for collectively removing and storing said positively identified containers; and a means associated with said transfer means for conveying said containers from a container receiving location to a container removing position of said transfer means.

5. The loading and transfer assembly of Claim 4 wherein said collective loading means, collective removing and storing means, and conveying means are mounted for rotation within said assembly and further comprise:
a first carousel associated with said collective loading means, said first carousel having a partially hollow inner core portion, and a peripheral portion having a plurality of radially extending slots for receiving a number of upstanding sample containers;

a second carousel associated with said conveying means, said second carousel located adjacent to said first carousel and having a plurality of slots circumscribed about its periphery, said slots positioned for receiving and retaining the sample containers; and a third carousel associated with said collective removing and storing means, said third carousel located adjacent to said second carousel and on a side substantially opposite that of the first carousel;
said third carousel having a partially hollow inner core portion, and a peripheral portion having a plurality of radially extending slots for receiving a number of upstanding sample containers.

6. The loading and transfer assembly of Claim 5 wherein the first removing means associated with said loading means further comprises:
a container displacing mechanism located within said hollow inner core portion, said mechanism positioned to laterally displace said containers from the container receiving slots of the first carousel to the container receiving slots of the second carousel in response to the operation of the chemical analyzer.

7. The loading and transfer assembly of Claim 5 wherein the second removing means associated with said transfer means further comprises:
a container displacing mechanism positioned within the second carousel to laterally displace said containers from the container receiving slots of the second carousel to the container receiving slots of the third carousel in response to the operation of the chemical analyzer.

8. The loading and transfer assembly of Claim 6 or 7 wherein the container displacing mechanism further comprises:

a laterally movable arm having at one end an abutment member for engaging the surface of the container, and a horizontal member connected thereto for engaging a motor and transmitting a lateral move-ment to said container in response to said motor.

9. The loading and transfer assembly of Claim 6 where-in the container displacing mechanism further comprises:
a tension laterally movable arm. having at one end an abutment member for engaging the surface of the container, and a horizontal member connected thereto for engaging a motor and transmitting a lateral movement to said container in response to said motor;
wherein the tension arm further comprises a means for disengaging said horizontal member from said motor in response to a resistance encountered by said laterally displaced containers.

10. The loading and transfer assembly of Claim 9 further comprising a means associated with the second carousel for preventing the non-gentle transfer of the sample container from said first carousel.

11. The loading and transfer assembly of Claim 10 wherein the preventing means comprises:
a spring-tension device located adjacent to the container receiving slot and having an obliquely upstand-ing bar member mounted to said carousel at a bottom end thereof, and a contact member disposed at the top end of said bar member, said contact member positioned to contact the upper portion of said containers during transfer thereof.

12. The loading and transfer assembly of Claim 1 wherein said logic means further comprises a means for operating and selecting the tests to be performed by said chemical analyzer in response to the sample container identification obtained by said identifying means.

13. The loading and transfer assembly of Claim 1 further comprising:
a stat loading means associated with said transfer means for randomly introducing sample containers into said assembly in a position forward of pre-loaded containers in said loading means and rearward of said identifying means while maintaining the pre-loaded position of said containers in said assembly.

14. The loading and transfer assembly of Claim 13 wherein the stat loading means further comprises:
a carousel located adjacent to said loading means, said carousel having a plurality of slots circumscribed about its periphery positioned for receiving and retaining the sample containers therein;
a fixed sample container exchange slot position disposed at the point of intersection of said carousel with said loading means; and a plurality of designated stat-loading slots located rearward of said container-exchange slot position.

15. The loading and transfer assembly of Claim 1 further comprising:
a carousel associated with said transfer means;
said carousel being located adjacent to said leading means, and having a plurality of slots circumscribed about its periphery positioned for receiving and retaining the sample containers therein;

a first stat loading means associated with said carousel for randomly introducing sample containers into said assembly in a position forward of pre-loaded containers in said loading means and rearward of said identifying means while maintaining the pre-loaded position of said containers in said assembly; said first stat loading means comprising a fixed sample-container slot positioned disposed at the point of intersection of said carousel with said loading means; and a plurality of designated stat-loading slots located rearward of said container-exchange slot position; and a second stat loading means associated with said transfer means for randomly introducing sample containers into said assembly forward of pre-loaded containers in the loading and transfer means and rearward of said identifying means.

16. The loading and transfer assembly of Claim 14 further comprising:
a signaling means associated with said transfer means for indicating the rotational status of the carousel, said signaling means operating in response to the operation of said analyzer.

17. The loading and transfer assembly of Claim 15 wherein said signaling means further comprises a binary indicating device.

18. The loading and transfer assembly of Claim 17 wherein said binary indicating device comprises a pair of light emitting diodes for alternately indicating the status of the carousel.

19. The loading and transfer assembly of Claim 1 wherein the dispensing means further comprises:
a means for positioning said dispensing means to a predetermined height;

a means for detecting the fluid sample level in the container; and a means for adjusting the height of said sample container in response to said detection means so as to bring said fluid sample level to the predetermined height of said dispensing means.

20. The loading and transfer assembly of Claim 19 wherein said positioning means downwardly displaces said dispensing means to said predetermined height.

21. The loading and transfer assembly of Claim 20 wherein said positioning means further comprises a means for positioning said dispensing means downwardly to a position below said predetermined height.

22. The loading and transfer assembly of Claim 21 wherein said positioning means downwardly displaces said dispensing means below said predetermined height at a constant rate and in response to the operation of said analyzer.

23. The loading and transfer assembly of Claim 22 wherein the positioning means further comprises a means for successively positioning said dispensing means to height coinciding with the height of said fluid sample remaining in said container after dispensing therefrom.

24. The loading and transfer assembly of Claim 19 wherein the fluid level detecting means comprises:
a radiant energy emitter and a radiant energy detector located adjacent to a container-receiving position in said transfer means;
said radiant energy emitter and detector further positioned on substantially opposite sides of a plane defining the vertical axis of said container-receiving position such that the emission of radiant energy from the emitter is detected through reflectance from the meniscus of the fluid in a container.

25. The loading and transfer assembly of Claim 24 wherein the radiant energy detector further comprises:
a bifurcated housing having a first and second housing member;
said first housing member aligned for directly receiving reflected radiant energy from said meniscus;
said second housing member having arms extending on opposite sides of said first member;
a means for sensing radiant energy in each arm of the second housing member; and a means disposed at the branch point of said housing for directing radiant energy received through said first housing member to each sensing means of said second housing member.

26. The loading and transfer assembly of Claim 25 wherein said energy-directing means comprises a bifrontal reflective surface having a first and second surface extending outwardly and in a direction away from said first housing member.

27. The loading and transfer assembly of Claim 26 wherein the bifurcated housing is Y-shaped and the radiant energy is infrared radiation.

28. The loading and transfer assembly at Claim 19 wherein the height adjusting means further comprises:
a means associated with said transfer means for elevating said sample container to the predetermined height of said dispensing means;
and a means for retaining said container in an elevated position thereafter.

29. The loading and transfer assembly of Claim 28 wherein the elevation-retaining means further comprises:

a pair of spaced apart vertical posts mounted on said transfer means;

a horizontal base for supporting said container, said base movably secured at its opposite ends to the spaced apart vertical posts; and a movable friction member located adjacent to said horizontal base;

said friction member being engageable with at least one of said posts for frictionally retaining said base member at any vertical position along said posts.

30. The loading and transfer assembly of Claim 29 wherein said elevating means comprises an upstanding worm drive and gear assembly having a drive rotating means and a vertically movable nut positioned to engage the elevation retaining means and transmit an upward vertical movement thereto.

31. The loading and transfer assembly of Claim 28 further comprising a means for lowering said sample container from an elevated position.

32. The loading and transfer assembly of Claim 30 further comprising a means for lowering said sample container from its elevated position, said lowering means further comprising:

a pair of spaced apart vertical posts mounted on said transfer means;

a horizontal base for supporting said container, said base movably secured at its ends to the spaced apart vertical posts;
a movable friction member located adjacent said horizontal base;
said friction member being engageable with at least one of said posts for frictionally retaining said base member at any vertical position along said posts, and an upstanding worm drive and gear assembly having a driver rotating means and vertically movable nut positioned to engage the elevation retaining means and transmit a downward vertical movement thereto.

33. The loading and transfer assembly of claim 1, where-in identifying means further comprises a means for sensing an information code on said sample containers.

34. The loading and transfer assembly of Claim 33 where-in the information sensing means comprises:
a bar code sensor associated with said transfer means, said sensor located adjacent a sample container receiving position;
said bar code sensor positioned to sense a bar code on said containers;

35. The loading and transfer assembly of Claim 34 wherein the information sensing means further comprises:
a bar code sensor mounted for sensing a hori-zontally placed bar code on said container; and a means for rotating said bar code in front of said sensor.

36. The loading and transfer assembly of Claim 35 where-in the information sensing means further comprises:
a means for simultaneously rotating and vertic-ally elevating said container such that the bar code is spirally sensed by the bar code sensor.

37. The loading and transfer of assembly of Claim 35 wherein the rotating means further comprises:
a rotating member mounted adjacent the sample container receiving position;
said rotating member having an axis of rotation parallel to the axis of rotation of the container; and an edge portion of said rotating member positioned to reversibly engage the container.

38. The loading and transfer assembly of claim 35 further comprising:
a means associated with said bar code sensor for maintaining the sensor in a horizontal plane per-pendicular to the container during rotation thereof.

39. The loading and transfer assembly of Claim 38 where-in the maintaining means comprises:
a pair of space-apart vertical members secured to each other at both ends thereof;

said vertical members being mounted at a bottom end thereof on a base member associated with said transfer means, and coupled to the bar code sensor at a top end;
a horizontal engagement member connected to the top portion of said vertical members and positioned to engage the surface of said container.

40. The loading and transfer assembly of Claim 34 further comprising:
a means associated with said transfer means for distinguishing between the type of sample containers in said container receiving slot.

41. The loading and transfer assembly of Claim 40 wherein the container distinguishing means comprises:
a transmissive light source sensor mounted adjacent to said sample container retaining position;
said light source sensor mounted positioned to detect a nontransparent region on said container.