Method and apparatus for quantitation of relevant blood parameters

• US 5,567,869 A
• Filed: 08/03/1994
• Issued: 10/22/1996
• Est. Priority Date: 12/19/1991
• Status: Expired due to Fees

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Hauch, Ole, Knudsen, Jens B., Plum, Thomas M.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): LARKIN, DANIEL SEAN
• Application Number:
  US08/244,966
• Time in Patent Office: 811 Days
• Field of Search: 73/64.41, 73/64.43, 73/61.65, 73/61.69, 422/73, 422/82.05, 436/69, 436/70, 435/13, 128/637, 128/DIG. 22, 356/39
• US Class Current: 73/64.41
• CPC Class Codes: G01N 15/05 in blood
• CPC Class Codes: G01N 2015/055 for hematocrite determination
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 2021/1789 Time resolved
• CPC Class Codes: G01N 21/59 Transmissivity G01N21/25 takes precedence
• CPC Class Codes: Y10S 128/22 Blood coagulation

Abstract

A method for quantitation of blood parameters comprises the steps: provision of a sample of plasma, serum or blood, entering the sample into a cuvette with an internal dimension less than 1 mm, illuminating the sample by a light source, measuring and recording the changes of light properties caused by the sample as a function of time, calculating parameters of the recorded light signal/time curve such as slopes, extreme values, and the time distance between such extreme values, and interpreting the parameters as blood parameters. For the measurements, an apparatus is used comprising a cuvette (16, 17) with an internal dimension less than 1 mm, a light source (7, 9), means (8, 10) for measuring currently a light signal from the sample, means for recording the measured light signal values, and means for calculating parameters of the thereby defined light signal versus time graph.

Claims

1. A method for quantitation of blood parameters, said blood parameters being coagulation time, sedimentation rate, hemocrit, fibrinogen concentration, platelet related coagulation activity, activity of the fibrinolytic system of the blood, rate of fibrinogen degeneration, amount of fibrin, and original figrinogen concentration, comprising the following steps:

(a) providing a sample of plasma, serum or whole blood;

(b) entering the sample into a cuvette with an internal dimension less than 1 mm;

(c) illuminating the sample by a light source;

(d) measuring and recording the changes of light properties caused by the sample as a function of time to obtain a light signal versus time curve;

(e) calculating parameters of the recorded light signal/time curve; and

(f) interpreting the parameters as blood parameters.

2. A method according to claim 1, wherein the recording is made by frequently storing connected values for measured light signal and time elapsed from a starting moment for a measurement.

3. A method according to claim 1, wherein the time for a first extreme value caused by the introduction of the sample into the cuvette is interpreted as a starting moment for the measurement.

4. A method according to claim 1, wherein the time elapsing from a starting moment to a well defined point in relation to a second occurring extreme value is taken as an expression of the coagulation time.

5. A method according to claim 1, wherein the slope of the curve when passing from the first extreme value to a second extreme value is taken as an expression of the sedimentation rate.

6. A method according to claim 1, wherein the height of the curve when passing from the first extreme value to a second extreme value is taken as an expression of the hematocrit.

7. A method according to claim 1, wherein the difference between a second extreme value and a third extreme value is taken as an expression of the fibrinogen concentration.

8. A method according to claim 1, wherein the slope of the curve when passing from a second extreme value is taken as an expression of the fibrinogen concentration and platelet related coagulation activity.

9. A method according to claim 1, wherein the time it takes for the light signal curve to pass a third extreme value is calculated as a time interval from the moment when a light signal value passes a set value differing by a predetermined amount from this third extreme value when approaching this value, until the moment when the light signal value again passes this set value after having passed the third extreme value, and this calculated time is taken as an expression of activity of a fibrinolytic system.

10. A method according to claim 1, wherein the slope of the light signal curve when passing from a well-defined point in relation to its third extreme value to a well-defined point in relation to its fourth extreme value is taken as an expression of the rate of fibrin degeneration.

11. A method according to claim 1, wherein the difference between the value in a well-defined point in relation to a third extreme value and a well-defined point in relation to a fourth extreme value on the light signal curve is taken as an expression of fibrin in the sample and consequently of original fibrinogen concentration.

12. An apparatus for quantitation of blood parameters by performing the method according to claim 1, comprising

(a) a cuvette with an internal dimension less than 1 mm for receiving a blood sample;

(b) a light source for illuminating the sample;

(c) means for measuring the light signal from the sample in the cuvette;

(d) means for recording the measured light signal values;

(e) means for calculating the parameters of the recorded light signal versus time curve; and

(f) means for displaying the results of this calculation.

13. An apparatus according to claim 12, wherein the means for calculating further converts the calculated curve parameters to blood parameters.

14. An apparatus according to claim 13, wherein the cuvette is a capillary element.

15. An apparatus according to claim 14, wherein the cuvette is a capillary tube.

17. An apparatus according to claim 12, wherein the cuvette is mounted in a disposable part of the apparatus.

18. An apparatus according to claim 12, wherein the means for measuring the light signal comprises a light source and a light sensor facing each other on opposite sides of the cuvette.

19. An apparatus according to claim 12, further comprising a means for performing the current recording by storing at preset time intervals the measured translucence values, performing the calculations of the curve parameters on the basis of the stored values, and translating the curve parameters into blood parameters.

16. An apparatus according to clam 15, further comprising more parallel acting capillary tubes.