Method and device for measuring blood parameters

• US 6,510,330 B1
• Filed: 08/17/2001
• Issued: 01/21/2003
• Est. Priority Date: 11/30/1998
• Status: Expired due to Fees

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: Gambro AB (Baxter International Inc.)
• Inventors: Enejder, Annika
• Primary Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US09/856,765
• Time in Patent Office: 522 Days
• Field of Search: 600/310, 600/322, 600/326, 600/328, 356/39
• US Class Current: 600/322
• CPC Class Codes: G01N 21/532 with measurement of scattering and transmission

Abstract

Methods are disclosed for analysing the concentration of red blood cells in a flow of blood including flowing the blood through a cuvette, directing a light through the flow of blood, measuring light transmitted through the flow of blood to obtain a transmitted signal, measuring scattered light at a predetermined angle with respect to the direct transmission path through the flow of blood to obtain a scattered signal, and providing a ratio signal comprising the ratio between the scattered signal and the transmitted signal. Apparatus for analysing the concentration of red blood cells is also disclosed.

Claims

1. A method for analyzing the concentration of red blood cells in a flow of blood comprising flowing said blood through a cuvette, directing a light along a direct transmission path through said flow of blood in said cuvette, measuring light transmitted through said flow of blood along said direct transmission path to obtain a transmitted signal, measuring scattered light at a predetermined angle with respect to said direct transmission path to obtain a scattered signal, and providing a ratio signal comprising the ratio between said scattered signal and said transmitted signal.

2. The method of claim 1 wherein said predetermined angle is about 90°

.

3. The method of claim 1 wherein said predetermined angle is between 70°

and 110°

.

4. The method of claim 3 wherein said predetermined angle is between 80°

and 100°

.

5. The method of claim 1 including directing said light from a light emitting member, measuring said light transmitted along said direct transmission path by means of a first light sensitive member, and measuring said scattered light by means of a second light sensitive member.

6. The method of claim 5 including surrounding at least a portion of said cuvette with light absorbing material in order to increase the sensitivity of said ratio signal.

7. The method of claim 6 including emitting light having a restricted emission angle by means of said light emitting member.

8. The method of claim 6 including activating said light emitting member in a pulsed mode.

9. Apparatus for analyzing the concentration of red blood cells in a flow of blood comprising a cuvette for said flow of blood, a light emitting member for directing a light along a direct transmission path through said flow of blood in said cuvette, a first light sensitive member for measuring light transmitted through said flow of blood along said direct transmission path to obtain a transmitted signal, a second light sensitive member for measuring scattered light at a predetermined angle with respect to said direct transmission path to obtain a scattered signal, and calculation means for providing a ratio signal comprising the ratio between said scattered signal and said transmitted signal.

10. The apparatus of claim 9 wherein said predetermined angle is about 90°

.

11. The apparatus of claim 9 wherein said predetermined angle is between 70°

and 110°

.

12. The apparatus of claim 11 wherein said predetermined angle is between 80°

and 100°

.

13. The apparatus of claim 9 including light absorbing material surrounding at least a portion of said cuvette.

14. The apparatus of claim 13 wherein said light emitting member has a restricted emission angle.

15. The apparatus of claim 9 wherein said light emitting member is driven in a pulsed mode.