GB2048836A

GB2048836A - Improvements in blood testing apparatus

Info

Publication number: GB2048836A
Application number: GB8012115A
Authority: GB
Original assignee: GUEST Ltd
Current assignee: GUEST Ltd
Priority date: 1979-04-20
Filing date: 1980-04-11
Publication date: 1980-12-17
Also published as: GB2048836B

Abstract

A universal plastics plug 11 for a blood sedimentation rate test, has a stepped external surface 15, so as to fit within a wide range of collecting tubes 7, and a pierceable membrane (6), Figs. 2 and 3 (not shown). A pipette 8 is passed down the tapered open centre of plug 11 and having pierced the membrane mates with the plugs smallest internal diameter, thereby enabling standard pipettes to be used with a variety of types of collecting tubes. <IMAGE>

Description

SPECIFICATION Improvements in blood testing apparatus This invention relates to blood testing apparatus.

One frequently used blood test is the Erythrocyte sedimentation rate (ESR) test, in which a column of blood 200 mm high is observed after preset time limits, normally 1 hour and/or 2 hours, to measure the rate of settlement of the erythrocytes (red corpuscles).

Since blood tests are normally carried out on diseased patients, there is a considerable risk that the blood samples are infected, so it is necessary to prevent contamination as much as possible for the protection of laboratory staff and others. Accordingly, disposable equipment is much used.

Also, in order to reduce the shock effect on patients, use is now increasingly made of vacuum or suction collecting systems, rather than the conventional syringes. In such systems a collecting tube under high vacuum is closed by a rubber of like stopper. The stopper is pierced by a needle and the vacuum draws blood from the patient. When the needle is withdrawn from the stopper the latter seals itself. When an ESR test is to be made, the stopper has to be removed and a pipette, to hold the column of blood, is introduced into the tube. For other tests, the sample, or a portion of it may need to be transferred from the tube to a probe or to another vessel.

It is preferred in the ESR test that some sort of closure be in the tube around the pipette to prevent spillage and support the tube. In view of the number of different makes of blood collecting systems, which need to be usable with pipettes of a standard type, a suitable closure normally has to be designed for each different system. For the tests, it is preferred that a pierceable closure be used to protect the laboratory workers.

According to the present invention, there is provided a universal safety cap for use with a range of collecting tubes, comprising a hollow frusto-conical member of plastics material with a stepped external surface and having at least one end closed by a pierceable membrance.

The stepped external surface provide appropriate seating surfaces for a range of collecting tubes and the pipette passes down the open centre and mates with the narrowest diameter of the internal surface.

The invention also includes the combination of a pipette, a collecting tube and a cap comprising a hollow frusto-conical member of plastics material with a stepped external surface.

The invention will be further described with reference to the accompanying drawings, which show a preferred embodiment of the invention ant in which: Figure 1 is a vertical section through apparatus for carrying out a sedimentation rate test incorporating a cap and combination according to a preferred form of the invention; Figure 2 is a section, to an enlarged scale, of a cap shown in Figure 1; and Figure 3 shows a variation of the cap of Figure 3.

In Figure 1, there is shown a stand 1, which normally carries a plurality of samples for testing.

The stand comprises an upright back 2 which carries upper and intermediate guides 3 and 4 respectively, and a base 5 which carries a removable tray 6. The samples are collected in collecting tubes 7, only one of which is illustrated in Figure 1, and the colum of blood is supported in a pipette 8 extending down into the sample in the tube 7 and upwardly to a plug 9 of porous material, the lower boundary 10 of which is coincident with a standard mark for the top of the blood column, normally 200 mm. Between the pipette 8 and the tube 7 there is a universal safety cap 11 which is designed to prevent spillage of blood without preventing the induction of air into the tube 7 when the blood is being drawn up the pipette 8 by a suction source applied at the top thereof.

It will be seen that the pipette passes down through the centre portion 12 (see Figures 2 to 4) of the cap 11 and engages as a sliding but not tight fit on the narrowest portion 13 thereof. The outer surface of the cap 11 is stepped to provide a plurality of different usable diameters 14 so that the cap will fit tubes 7 of different sizes, and will also mate adequately with tubes which vary slightly from those sizes by virtue of the inclined connecting portions 1 5 between the usable diameters 14. The cap 11 is moulded in a suitable plastics material and is preferably slightly resilient to enable it to conform to collecting tubes 7 of wide manufacturing tolerances.

In Figure 2 the cap 11 is shown as having a pierceable membrane 1 6 at the wider end thereof, and in figures 3 and 4 at the narrower end thereof.

This membrane provides a temporary closure for the cap to prevent leakage or contamination of the blood in the tube 7, and may be pierced by the pipette 8 or by any other device introduced to remove the sample for analysis.

In use, for an ESR test, the collecting tube with its rubber stopper is brought to the laboratory, and the rubber stopper is removed and replaced by a cap 11, through which a pipette may then be introduced. the samples are set up in the stand 1 and the lifting of the column of blood performed successively by a suction line applied to the tops of the pipettes 8. The height of the column is maintained by the provison of the plug 9. At the conclusion of the test, the tray 6 is removed to ailow the tubes 7 and pipettes 8, and all the blood included therein to fall into a disposal bin or bag.

Various modifications may be made within the scope of the invention.

1. A universal safety cap for use with a range of collecting tubes, comprising a hollow frustoconical member of plastics material, with a stepped external surface and having at least one end closed by a pierceable membrane.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in blood testing apparatus This invention relates to blood testing apparatus. One frequently used blood test is the Erythrocyte sedimentation rate (ESR) test, in which a column of blood 200 mm high is observed after preset time limits, normally 1 hour and/or 2 hours, to measure the rate of settlement of the erythrocytes (red corpuscles). Since blood tests are normally carried out on diseased patients, there is a considerable risk that the blood samples are infected, so it is necessary to prevent contamination as much as possible for the protection of laboratory staff and others. Accordingly, disposable equipment is much used. Also, in order to reduce the shock effect on patients, use is now increasingly made of vacuum or suction collecting systems, rather than the conventional syringes. In such systems a collecting tube under high vacuum is closed by a rubber of like stopper. The stopper is pierced by a needle and the vacuum draws blood from the patient. When the needle is withdrawn from the stopper the latter seals itself. When an ESR test is to be made, the stopper has to be removed and a pipette, to hold the column of blood, is introduced into the tube. For other tests, the sample, or a portion of it may need to be transferred from the tube to a probe or to another vessel. It is preferred in the ESR test that some sort of closure be in the tube around the pipette to prevent spillage and support the tube. In view of the number of different makes of blood collecting systems, which need to be usable with pipettes of a standard type, a suitable closure normally has to be designed for each different system. For the tests, it is preferred that a pierceable closure be used to protect the laboratory workers. According to the present invention, there is provided a universal safety cap for use with a range of collecting tubes, comprising a hollow frusto-conical member of plastics material with a stepped external surface and having at least one end closed by a pierceable membrance. The stepped external surface provide appropriate seating surfaces for a range of collecting tubes and the pipette passes down the open centre and mates with the narrowest diameter of the internal surface. The invention also includes the combination of a pipette, a collecting tube and a cap comprising a hollow frusto-conical member of plastics material with a stepped external surface. The invention will be further described with reference to the accompanying drawings, which show a preferred embodiment of the invention ant in which: Figure 1 is a vertical section through apparatus for carrying out a sedimentation rate test incorporating a cap and combination according to a preferred form of the invention; Figure 2 is a section, to an enlarged scale, of a cap shown in Figure 1; and Figure 3 shows a variation of the cap of Figure 3. In Figure 1, there is shown a stand 1, which normally carries a plurality of samples for testing. The stand comprises an upright back 2 which carries upper and intermediate guides 3 and 4 respectively, and a base 5 which carries a removable tray 6. The samples are collected in collecting tubes 7, only one of which is illustrated in Figure 1, and the colum of blood is supported in a pipette 8 extending down into the sample in the tube 7 and upwardly to a plug 9 of porous material, the lower boundary 10 of which is coincident with a standard mark for the top of the blood column, normally 200 mm. Between the pipette 8 and the tube 7 there is a universal safety cap 11 which is designed to prevent spillage of blood without preventing the induction of air into the tube 7 when the blood is being drawn up the pipette 8 by a suction source applied at the top thereof. It will be seen that the pipette passes down through the centre portion 12 (see Figures 2 to 4) of the cap 11 and engages as a sliding but not tight fit on the narrowest portion 13 thereof. The outer surface of the cap 11 is stepped to provide a plurality of different usable diameters 14 so that the cap will fit tubes 7 of different sizes, and will also mate adequately with tubes which vary slightly from those sizes by virtue of the inclined connecting portions 1 5 between the usable diameters 14. The cap 11 is moulded in a suitable plastics material and is preferably slightly resilient to enable it to conform to collecting tubes 7 of wide manufacturing tolerances. In Figure 2 the cap 11 is shown as having a pierceable membrane 1 6 at the wider end thereof, and in figures 3 and 4 at the narrower end thereof. This membrane provides a temporary closure for the cap to prevent leakage or contamination of the blood in the tube 7, and may be pierced by the pipette 8 or by any other device introduced to remove the sample for analysis. In use, for an ESR test, the collecting tube with its rubber stopper is brought to the laboratory, and the rubber stopper is removed and replaced by a cap 11, through which a pipette may then be introduced. the samples are set up in the stand 1 and the lifting of the column of blood performed successively by a suction line applied to the tops of the pipettes 8. The height of the column is maintained by the provison of the plug 9. At the conclusion of the test, the tray 6 is removed to ailow the tubes 7 and pipettes 8, and all the blood included therein to fall into a disposal bin or bag. Various modifications may be made within the scope of the invention. CLAIMS

2. In combination, a pipette, a collecting tube and a cap comprising a hollow frusto-conical member of plastics material with a stepped external surface, with the cap in position on an open end of the collecting tube and the pipette passing through the centre of the cap and mating with the narrowest diameter of its internal surface.

3. In combination, a pipette, a collecting tube and a cap comprising a hollow frusto-conical member of plastics material with a stepped external surface, in which the cap is adapted to fit in the open end of the collecting tube and the pipette is adapted to pass down to the open centre of the cap and to mate with the narrowest diameter of the internal surface thereof.

4. A combination as claimed in claim 3, in which the cap has at least one end closed by a pierceable membrane.

5. A combination as claimed in claim 2, 3 or 4, in which the pipette is a siiding but not tight fit in the narrowest diameter.

6. A combination as claimed in claim 2, 3, 4 or 5, in which the pipette has a plug therein extending upwardly from a desired level of the top of a column of blood.

7. A universal safety cap, a combination of cap, pipette and collecting tube substantially as hereinbefore described with reference to the accompanying drawings.