Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12Q—MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS; COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES
  • C12Q1/00—Measuring or testing processes involving enzymes, nucleic acids or microorganisms; Compositions therefor; Processes of preparing such compositions
  • C12Q1/001—Enzyme electrodes
  • C12Q1/005—Enzyme electrodes involving specific analytes or enzymes
  • C12Q1/006—Enzyme electrodes involving specific analytes or enzymes for glucose
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
  • A61B5/1486—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using enzyme electrodes, e.g. with immobilised oxidase
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/483—Physical analysis of biological material
  • G01N33/487—Physical analysis of biological material of liquid biological material
  • G01N33/4875—Details of handling test elements, e.g. dispensing or storage, not specific to a particular test method
  • G01N33/48771—Coding of information, e.g. calibration data, lot number
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
  • A61B2560/04—Constructional details of apparatus
  • A61B2560/0406—Constructional details of apparatus specially shaped apparatus housings
  • A61B2560/0418—Pen-shaped housings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S435/00—Chemistry: molecular biology and microbiology
  • Y10S435/817—Enzyme or microbe electrode

Definitions

• the invention relates to a device for measuring and displaying the concentration of glucose in blood, according to the preamble of claim 1.
• Such glucose measuring devices for diabetics are already known and essentially consist of the actual measuring device (gluconeter) and replaceable sensors (glucose sensors) which can be inserted therein and to which the blood to be determined is applied in small quantities.
• the user draws the necessary blood in the conventional manner by pricking the fingertip.
• the sensor When the sensor is inserted, its biomembrane is electrically contacted with the measuring device, so that the voltage and / or current changes in the active biomembrane of the sensor caused by the different glucose contents are passed on to the measuring device.
• the relevant measuring range for blood glucose in diabetics is between 4 and 15 amol / l (s 70 - 270 mg / dl).
• the measuring range of such devices is typically 3 - 16 aaol / 1 (s 50 - 300 mg / dl).
• the prior art glucose meters are too complicated, difficult to use, unreliable and therefore dangerous for the patient.
• the biomembrane of glucose sensors the active component of which consists of an unstable enzyme, for example glucose oxidase
• the active component of which consists of an unstable enzyme for example glucose oxidase
• the invention seeks to remedy this.
• the invention has for its object to provide a glucose meter with which it is possible to regulate all essential influencing factors already during the manufacture of the glucose meter by means of a one-time calibration that cannot be changed for the patient while taking into account the age-dependent changes in the influencing variables.
• the invention achieves the stated object with a glucose measuring device which has the features of claim 1.
• the glucose measuring device is given to the patient in the form of a display device (computer with time measuring device) together with 200-300 sensors as a complete package. This number of sensors is usually sufficient for half a year to a whole year. Due to the specifically coordinated measurement and evaluation characteristics of the display device and the disposable sensors, as well as the adaptation of the evaluation parameters to the age-dependent measurement parameters of the sensors by means of the internal time meter of the display device, on the one hand a high accuracy of the measurement result is guaranteed and on the other hand a high level of safety in operation is guaranteed.
• the advantages achieved by the invention are essentially to be seen in the fact that, thanks to the glucose measuring device according to the invention, the patient no longer has to carry out a calibration of the device to the disposable sensors to be contacted, and neither an initial calibration during commissioning nor a subsequent calibration during the life of the device. Thanks to the automatic correction of all important parameters and the preferably provided limitation of the life of the device, no maintenance is required.
• the glucose concentration diagram which can be both measurement current-dependent and measurement-voltage-dependent, is determined by means of a one-point or multi-point calibration.
• the calibration can be carried out either hardware-wise, for example by trimming in the analog part (calibration), or software-wise, for example using a table in the invoice memory. It permits disposable disposable disposable items that come with the display device and come from a single production batch Sensors precisely coordinated by the manufacturer, which rules out patient errors in this delicate operation.
• the mutually facing, connectable ends of the sensor and display device have mutually corresponding cams and grooves.
• the exact form and arrangement of these key / lock elements is changed periodically during the manufacture of the sensors and display devices, so that sensors from the previous product batches - with an aging-related weakened sensitivity of the enzyme immobilized on the bio-membrane - no longer use the display devices from the new production batch can be used. This means that a further source of errors and dangers on the patient side can be largely eliminated.
• an additional, preferably in the immediate vicinity of, the bio-membrane of the sensor is provided.
• Brought temperature sensor is provided, which takes the temperature dependence of the glucose concentration diagram into account.
• the sensors supplied are expediently stored in a drawer (magazine) provided in the display device, into which the temperature sensor opens.
• a drawer magazine
• temperature fluctuations which can easily be in the range between 15-25 degrees, can be taken into account, which leads to a considerably more reliable measurement of the glucose values.
• the shelf life is limited to approximately one year, which is why, in a further preferred embodiment of the device according to the invention, the computer is preprogrammed such that after a predetermined service life or number of measurements carried out, the automatic and unchangeable shutdown and the device is inoperative.
• This function can be easily implemented with the existing inner timepiece and is not to be underestimated.
• Limiting the service life of the gli-3 measuring device prevents the use of sensors that are too old and therefore no longer reliable. The patient is thus forced to have a new device delivered by the doctor with new sensors that are matched to it, which in turn ensures a faultless and reliable determination of the blood glucose values.
• the lifespan of the Energy-supplying battery should expediently be matched to the preprogrammed service life of the device, so that there is no need to change the battery.
• the computer is expediently preprogrammed such that the automatic and unchangeable correction of the glucose concentration diagram, which is influenced by the time measuring device and takes into account the time-dependent properties of the disposable sensors, is carried out by means of a batch-dependent reaction sensitivity diagram. It is thus possible to take into account the reaction sensitivity of the enzyme immobilized on the biomembrane of the sensor, for example glucose oxidase, which decreases legally with increasing aging. The reduction in activity obeys a first approximation of a decreasing e-function, which can be saved in the form of a program or a table in the computer.
• the computer has a memory with which the measured blood glucose values can be stored for later evaluations.
• This makes it possible, for example, to transfer the glucose values of a whole measurement period (30-50 measurements) to an external device (eg personal computer), where they can be processed and evaluated to support the therapy.
• the internal clock is designed in such a way that the patient cannot set it himself. If necessary, it can be regulated externally by the doctor. However, the time is only interesting in connection with the stored measured values for the blood glucose content, so that the clock adjustment can expediently take place when the values are read out.
• Fig. 1 shows a schematic overall view of the Hess advocatess with a measuring strip inserted
• Fig. 2 shows a side view of the measuring device with cover cap
• FIG. 3 shows a top view of a sensor
• Fig. 4 shows a front view of the sensor
• Fig. 5 shows a front view of the display device
• FIG. 6 shows a diagram of glucose concentration / measuring current with different curves in batches and their aging dependency
• Fig. 7 shows a reaction sensitivity diagram.
• the measuring device 2 shown in the measuring state in FIG. 1 with the sensor 1 inserted essentially consists of a computer 3 with an internal clock 4 and a memory 7, a temperature sensor 6, a battery 10 and a push button 8 which sets all functions of the device in motion.
• the end of the device 2 intended for the plug-in contact with the sensor 1 is closed in the idle state, as shown in FIG. 2, with the clip-on clip 16, which also serves as a magazine for the sensors 1 which have not yet been used.
• This has the advantage that the temperature sensor 6 raises a value that is as close as possible to the actual temperature of the sensor 1 and forwards it to the computer 3.
• the sensor 1 which is shown in detail in FIGS. 1, 3 and 4, consists of an elongated strip made of plastic, which has the electrical contacts 12 for connection to the display device 2 at one end and a grip surface 11 for the latter at the other end Manipulation (plugging in and unplugging).
• the bio-membrane 9 In the center of the sensor 1, the bio-membrane 9 is arranged, to which the blood drop to be measured is to be applied.
• the biomembrane 9 consists of an amperometric electrode with an enzyme membrane which consists of glucose oxidase.
• a cam 13 is fitted between the electrical contacts 12, which fits into a corresponding groove 15 of the plug-side end of the display device 2 (FIG. 5).
• these key / lock elements 13, 15 is expediently changed every 6 to 12 months in the manufacture of sensors 1 and display devices 2, so that sensors 1 of the earlier production batches - with an aging-related weakened reaction sensitivity of the glucose oxidase - also the display devices 2 from the new production batch can no longer be used.
• this key / lock security device 13, 15 it is also possible to provide the sensors 1 with a bar code (bar code) which can only be read by a display device 2 authorized for these sensors 1.
• the manufacturer calibrates it to the sensors 1 to be supplied at the same time, ie the zero setting of the computer 3 is correlated in an invariable manner for the patient with the date of manufacture of the disposable sensors 1.
• the enzyme eg glucose oxidase
• the bio-membrane 9 of the sensor 1 shows a more or less high activity (batch A: calibration curve A c / Batch B: calibration curve B "/ batch C: calibration curve C Q ).
• the batch-dependent glucose calibration curve A ", B", C "is linear and in a first approximation has a constant slope.
• a one-point calibration is therefore usually sufficient for the calibration process.
• a two- or multi-point calibration would be necessary for more complicated calibration curves, which can result when using other enzymes.
• the activity of the enzyme decreases with advancing age, which is shown in the glucose concentration diagram 5 (FIG. 6) by a shift in the calibration curves A 0 , B 0 , C 0 down (A t , B,, C t ) manifested.
• the computer 3 can automatically determine the currently valid glucose calibration curve, for example C t (for sensors of batch C of age t), which is not influenced by the patient. perform, which takes into account the time-dependent properties of the bio-membrane 9 of the disposable sensors 1. All calibration curves shown in FIG.

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Priority Applications (3)

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Cited By (9)

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• 1989
  • 1989-07-07 CH CH2535/89A patent/CH677149A5/de not_active IP Right Cessation
• 1990
  • 1990-06-14 DE DE59005357T patent/DE59005357D1/de not_active Expired - Lifetime
  • 1990-06-14 US US07/656,135 patent/US5695623A/en not_active Expired - Fee Related
  • 1990-06-14 WO PCT/CH1990/000146 patent/WO1991000998A1/de active IP Right Grant
  • 1990-06-14 EP EP90908452A patent/EP0436679B1/de not_active Expired - Lifetime

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