PAPER BASED SPECTROPHOTOMETRIC DETECTION OF BLOOD HEMOGLOBIN CONCENTRATION

• US 20120257188A1
• Filed: 04/06/2012
• Published: 10/11/2012
• Est. Priority Date: 04/08/2011
• Status: Active Grant

• Current Assignee: CCW SAS, Rice University
• Original Assignee: Rice University
• Inventors: Richards-Kortum, Rebecca Rae, Yan, Jasper S., Bond, Meaghan McNeill, Wright, John Neil, Elguea, Carlos
• Granted Patent: US 8,730,460 B2
• Time in Patent Office: Days
• US Class Current: 356/40
• CPC Class Codes: G01N 2021/3144 for oxymetry
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 33/49 Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80

Abstract

The present disclosure relates to the use of a paper medium to measure blood hemoglobin concentration. In certain embodiments, spectrophotometric techniques are used to measure light transmission at specified wavelengths through a paper medium containing a blood sample. The light transmission information is then used in the calculation of blood hemoglobin concentration. In certain embodiments, the paper medium may be chemically treated to lyse the blood sample prior to measurement of the light transmission information.

Claims

1. A method for measuring hemoglobin concentration, comprising the acts of:

emitting a first wavelength of light through a blood sample on a paper medium;

detecting absorbance of the first wavelength of light;

emitting a second wavelength of light through the blood sample on the paper medium;

detecting absorbance of the second wavelength of light; and

calculating a hemoglobin concentration associated with the blood sample based on the detected absorbance of the first wavelength of light and the detected absorbance of the second wavelength of light.

2. The method of claim 1 wherein the second wavelength of light is equal to or greater than 600 nm.

3. The method of claim 1 wherein the first wavelength of light is about 590 nm.

4. The method of claim 1 wherein the blood sample is lysed prior to the first wavelength or the second wavelength being emitted.

5. The method of claim 1, wherein the blood sample is dried on the paper medium for about ten minutes.

6. The method of claim 1, wherein the blood sample is dried on the paper medium for about thirty minutes.

7. The method of claim 1, wherein the first wavelength of light is absorbed by hemoglobin in the blood sample and the second wavelength of light is minimally absorbed by hemoglobin in the blood sample relative to the first wavelength.

8. The method of claim 1, wherein the blood sample formed on the paper medium has a diameter of 3 mm or greater.

9. The method of claim 1, wherein the paper medium comprises one of a filter paper medium or a chromatography paper medium.

10. The method of claim 1, wherein the act of calculating the hemoglobin concentration employs an empirically derived correlation between optical density and hemoglobin concentration.

11. The method of claim 1, wherein the first wavelength of light constitutes an isobestic point for oxyhemoglobin and deoxyhemoglobin.

12. One or more machine readable media encoding routines that, when executed by a processor, cause acts to be performed comprising:

receiving a first input indicative of absorbance of light at a first wavelength through a blood sample on a paper medium;

receiving a second input indicative of absorbance of light at a second wavelength through the blood sample on the paper medium;

correcting for baseline intensity in the first input based on the second input to generate a normalized measure of absorbance by hemoglobin;

calculating a hemoglobin concentration using the normalized measure.

13. The one or more machine readable media of claim 12, wherein the hematocrit is calculated using an empirically determined correlation or constant relating optical density and hemoglobin concentration.

14. The one or more machine readable media of claim 12, wherein the first wavelength of light is about 590 nm.

15. The one or more machine readable media of claim 12, wherein the second wavelength of light is about 730 nm.

16. The one or more machine readable media of claim 12, wherein correcting for baseline intensity in the first input comprises subtracting the second input from the first input.

17. The one or more machine readable media of claim 12, wherein the first wavelength of light constitutes an isobestic point for oxyhemoglobin and deoxyhemoglobin.

18. A method for measuring hemoglobin concentration, comprising the acts of:

measuring the absorption of light by a blood sample on a paper medium at two wavelengths;

subtracting a value representative of the absorption of light at the second wavelength from a value representative of the absorption of light at the first wavelength to derive a normalized absorption value; and

calculating a hemoglobin concentration based on the normalized absorption value using an empirically determined correlation or constant relating optical density and hemoglobin concentration.

19. The method of claim 18, wherein the blood sample comprises lysed blood cells.

20. The method of claim 18, wherein the blood sample is lysed on the paper medium prior to the absorption of light being measured.