Analysis method and system therefor

• US 20030123047A1
• Filed: 12/20/2002
• Published: 07/03/2003
• Est. Priority Date: 12/28/2001
• Status: Active Grant

• Current Assignee: Hemocue AB (Danaher Corporation)
• Original Assignee: Hemocue AB (Danaher Corporation)
• Inventors: Pettersson, Joakim, Svensson, Johnny
• Granted Patent: US 6,831,733 B2
• Time in Patent Office: Days
• US Class Current: 356/39
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence

Abstract

The invention concerns a method for quantitative hemoglobin determination in undiluted, unhemolyzed whole blood comprising the steps of:

providing a disposable, capillary, which has an optical path length of less than 1 mm;

filling said cuvette with a sample of unaltered whole blood;

performing a first absorption measurement at a wavelength in the range 490-520 nm directly on the sample in the cuvette, and

further conducting a second absorption measurement, and

processing results of the first and second absorption measurements to determine the concentration of hemoglobin in the sample, wherein the step of processing comprises compensating for scattering in the sample, said compensating being dependent on the result of the second absorption measurement.

A system for implementing the method is also disclosed.

Claims

1. A method for quantitative hemoglobin determination in undiluted, unhemolyzed whole blood comprising the steps of:

providing a disposable, capillary curvette, which has an optical path length of less than 1 mm;

filling said cuvette with a sample of unaltered whole blood;

performing a first absorption measurement at a wavelength in the range 490-520 nm directly on the sample in the cuvette,

further conducting a second absorption measurement, and

processing results of the first and second absorption measurements to determine the concentration of hemoglobin in the sample, wherein the step of processing comprises compensating for scattering in the sample, said compensating being dependent on the result of the second absorption measurement.

2. The method according to claim 1 wherein the first absorption measurement is performed at a wavelength in the range 500-510 nm, more preferably at 506 nm.

3. The method according to claim 1 wherein the second absorption measurement is performed at a wavelength in the range 650-1200 nm, more preferably in the range 850-910 nm, most preferably in the range 860-900 nm.

4. The method according to claim 1 wherein the absorption measurement is performed in a photometer without an absorption filter or an interference filter, which provide correction for variations in the detector sensitivity and in the effective optical path length.

5. The method according to claim 1 wherein said cuvette has an optical path length of less than 0.2 mm.

6. The method according to claim 5 wherein said cuvette has an optical path length in the range 0.05-0.2 mm.

7. The method according to claim 1 wherein said processing is performed by a predetermined algorithm.

8. The method according to claim 7 wherein said processing determines the concentration of hemoglobin in the sample by computing the following formula:

[Tot Hb]=(Abs₁−

Abs₂)·

k+F(Abs₂)

wherein [Tot Hb] is the total concentration of hemoglobin in the sample, Abs₁ is the measured absorbance of the first absorption measurement, Abs₂ is the measured absorbance of the second absorption measurement, k is a calibration coefficient, which depends on the measurement arrangement, and F(Abs₂) is a function that depends on the measured absorbance of the second absorption measurement.

9. A method for determining a concentration of hemoglobin in a sample of undiluted, unhemolyzed whole blood from a result of a first absorption measurement on the sample performed at a wavelength in the range 490-520 nm and a result of a second absorption measurement on the sample, said method comprising:

processing the results of the first and second absorption measurements to determine the concentration of hemoglobin in the sample, wherein the step of processing comprises compensating for scattering in the sample, said compensating being dependent on the result of the second absorption measurement.

10. The method according to claim 9 wherein said processing determines the concentration of hemoglobin in the sample by computing the following formula:

[Tot Hb]=(Abs₁−

Abs₂)·

k+F(Abs₂)

wherein [Tot Hb] is the total concentration of hemoglobin in the sample, Abs₁ is the measured absorbance of the first absorption measurement, Abs₂ is the measured absorbance of the second absorption measurement, k is a calibration coefficient, which depends on the measurement arrangement, and F(Abs₂) is a function that depends on the measured absorbance of the second absorption measurement.

11. The method according to claim 9 wherein the first absorption measurement is performed at a wavelength in the range 500-510 nm, more preferably at 506 nm.

12. The method according to claim 9 wherein the second absorption measurement is performed at a wavelength in the range 650-1200 nm, more preferably in the range 850-910 nm, most preferably in the range 860-900 nm.

13. A system for quantitative hemoglobin determination in undiluted, unhemolyzed whole blood comprising:

means for emitting light at a first wavelength in a first range of 490-520 nm and at a second wavelength in a second range,

a cuvette holder arranged to receive a capillary cuvette, which has an optical path length of less than 1 mm and holds a sample of unaltered whole blood,

a detector for detecting light transmitted through the sample in a first absorption measurement for light in said first range and in a second absorption measurement for light in said second range, and

a processing unit for processing results of the first and second absorption measurements to determine the concentration of hemoglobin in the sample, wherein the processing comprises compensating for scattering in the sample, said compensating being dependent on the result of the second absorption measurement.

14. The system according to claim 13 wherein said means for emitting light, cuvette holder and detector are arranged in a photometer.

15. The system according to claim 14 wherein said processing unit is embedded in the photometer.

16. The system according to claim 14 wherein said processing unit is connected to the photometer.

17. The system according to claim 13 wherein a detecting area of the detector has a size such that essentially only directly transmitted light is detected.

18. The system according to claim 13 wherein the detector is arranged closer than 10 mm to the sample holder.

19. The system according to claim 13 wherein said means for emitting light comprises one light source, which is arranged to emit light at the first wavelength and to emit light at the second wavelength.

20. The system according to claim 13 wherein the means for emitting light comprises a first light source, which is arranged to emit light at the first wavelength, and a second light source, which is arranged to emit light at the second wavelength.

21. The system according to claim 13 wherein the first wavelength emitted by the means for emitting light is in the range 500-510 nm, more preferably at 506 nm.

22. The system according to claim 13 wherein the second wavelength emitted by the means for emitting light is in the range 650-1200 nm, more preferably in the range 850-910 nm, most preferably in the range 860-900 nm.

23. The system according to claim 13 wherein the cuvette holder is arranged to receive a cuvette, which has an optical path length of less than 0.2 mm.

24. The system according to claim 23 wherein the cuvette holder is arranged to receive a cuvette, which has an optical path length in the range 0.05-0.2 mm.

25. The system according to claim 13 wherein said processing unit uses a predetermined algorithm for performing said processing.

26. The method according to claim 25 wherein said processing determines the concentration of hemoglobin in the sample by computing the following formula:

[Tot Hb]=(Abs₁−

Abs₂)·

k+F(Abs₂)

wherein [Tot Hb] is the total concentration of hemoglobin in the sample, Abs₁ is the measured absorbance of the first absorption measurement, Abs₂ is the measured absorbance of the second absorption measurement, k is a calibration coefficient, which depends on the measurement arrangement, and F(Abs₂) is a function that depends on the measured absorbance of the second absorption measurement.