Method and apparatus for screening plasma for interferents in plasma from donor blood bags

• US 6,268,910 B1
• Filed: 09/03/1999
• Issued: 07/31/2001
• Est. Priority Date: 03/03/1997
• Status: Expired due to Term

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: CME Telemetrix, Inc.
• Inventors: Samsoondar, James, Given, Douglas George
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US09/367,863
• Time in Patent Office: 697 Days
• Field of Search: 356/39, 356/43, 356/364, 356/73, 356/40, 374/159, 374/161, 374/126, 604/27, 604/28, 604/39, 604/43, 604/54, 604/66, 604/67, 604/320, 604/325, 128/637, 128/638, 128/760, 128/7
• US Class Current: 356/39
• CPC Class Codes: A61M 1/0236 with sampling means, e.g. sample bag or sampling port
• 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

Abstract

An apparatus and a method whereby plasma integrity of plasma contained in a blood bag is rapidly and accurately assessed without compromising the sterility of the plasma, or destroying any of its components. This is achieved through spectral data which is used in a novel way so as to determine if a plasma specimen representative of plasma in a blood bag contains interferents and if so, to what extent. The apparatus and method analyse plasma contained in two bags whereby tubing connects the two bags. A lamp is used to irradiate the specimen, and a spectrophotometer is used to measure radiation from the specimen. The apparatus and method allow for determination where both the bags and tubings are translucent and contain writing on their surfaces (e.g., proprietary information), and the light is transmitted through the writings, plastic, and the plasma contained in the bag or tubing.

Claims

1. An apparatus for determining the concentration of at least one interferent in plasma in tubing where said tubing connects containers of said plasma, the apparatus comprising:

(A) a tubing holder comprising;

(i) a stationary part having a cavity adapted to accept said tubing;

(ii) a first optical fibre directed into said cavity positioned to transmit radiation into said tubing;

(iii) a second optical fibre directed into said cavity positioned to receive radiation from said tubing, said first and second fibres being stationary and defining a constant fixed optical path length through said tubing and plasma across said cavity; and

(iii) a lid which covers said cavity;

(B) a lamp connected to said first fibre to provide said radiation;

(C) a spectrophotometer to measure said received radiation from said second fibre; and

(D) a computer means connected to said spectrophotometer for calculating a concentration of said at least one interferent based on said measurement to provide said concentration.

2. The apparatus of claim 1 wherein said computer means calculates said concentration by combining first derivatives of at least two portions of a spectrum generated from said measured radiation to provide said concentration.

3. The apparatus of claim 1 wherein the tubing is translucent and contains writing on its surface and the radiation is transmitted through the writing, tubing and the plasma contained in the tubing.

4. The apparatus of claim 1 wherein the optical fibres are positioned to measure reflectance of the radiation.

5. The apparatus of claim 2 where at the least one interferent in plasma is selected from the group consisting of haemoglobin, bilirubin, biliverdin, equivalent intralipid, and methylene blue.

6. An apparatus for determining the concentration of at least one interferent in plasma in a blood bag, the apparatus comprising:

(A) a receptacle for receiving said bag, said receptacle comprising;

(i) a cavity for receiving a comer of said blood bag, said cavity comprising two walls of fixed position which define a V-shaped receptor for said comer of said bag;

(ii) a first optical fibre directed into said cavity positioned to transmit radiation into said bag;

(iii) a second optical fibre directed into said cavity positioned to receive radiation from said bag, said first and second fibres being stationary and defining a constant fixed optical path length through said bag and plasma across said cavity;

(B) a lamp connected to said first fibre to provide said radiation;

(C) a spectrophotometer to measure said received radiation from said second fibre; and

(D) a computer means connected to said spectrophotometer for calculating a concentration of said at least one interferent based on said measurement to provide said concentration.

7. The apparatus of claim 6 wherein said computer means calculates said concentration by combining first derivatives of at least two portions of a spectrum generated from said measured radiation to provide said concentration.

8. The apparatus of claim 6 wherein said plasma bag is translucent and contains writing on its surface and said radiation is transmitted through said writing bag and said plasma.

9. The apparatus of claim 6 wherein the optical fibres are positioned to measure reflectance of the radiation.

10. The apparatus of claim 7 where said at least one interferent in plasma is selected from the group consisting of haemoglobin, bilirubin, biliverdin, equivalent intralipid, and methylene blue.

11. A method for determining the concentration of at least one interferent in plasma contained in two bags, said method comprising the steps of:

(A) providing a tubing and connecting said bags such that plasma can flow from said bags into said tubing;

(B) providing a lamp to irradiate said plasma in said tubing;

(C) providing means for directing radiation into said tubing and means for receiving radiation from said tubing such that a constant fixed optical path length is established between said means for directing and said means to receive radiation across said tubing and plasma;

(D) irradiating said tubing;

(E) providing a spectrophotometer to measure radiation from said tubing; and

(F) calculating a concentration of said at least one interferent based on said measurement to provide said concentration.

12. The method of claim 11 wherein said calculation combines first derivatives of at least two portions of a spectrum generated from said measured radiation to provide said concentration.

13. The method of claim 11 wherein said tubing is translucent and contains writing on its surface and irradiation is transmitted through the writing, tubing and a plasma contained in the tubing.

14. The method of claim 11 wherein the radiation is reflected from a reflective surface placed behind the tubing.

15. The method of claim 12 wherein light leakages are compensated for by measuring dark current for both sample and reference measurements.

16. The method of claim 12 wherein the at least one interferent in plasma is selected from the group consisting of haemoglobin, bilirubin, biliverdin, equivalent intralipid, and methylene blue.

17. The method of claim 16 wherein absorbance is measured and such measurements are incorporated into the following algorithms for each of haemoglobin, bilirubin, biliverdin, equivalent intralipid, and methylene blue, respectively:

18. A method for determining the concentration of at least one interferent in plasma contained in a blood collection bag, the method comprising the steps of:

(A) providing a blood collection bag containing plasma;

(B) providing a lamp to irradiate said plasma in said bag;

(C) providing means for directing radiation into said bag;

means for receiving radiation from said bag such that a constant fixed optical path length is established from said means to direct to said means to receive radiation across said bag and plasma;

(D) irradiating said bag;

(E) providing a spectrophotometer to measure radiation from said bag; and

(F) calculating a concentration of said at least one interferent based on said measurement to provide said concentration.

19. The method of claim 18 wherein said calculation combines first derivatives of at least two portions of a spectrum generated from said measured radiation to provide said concentration.

20. The method of claim 18 wherein the bag is translucent and contains writing on its surfaces and said radiation is transmitted through said writing, wall and plasma contain in said bag.

21. The method of claim 18 wherein said radiation is measured and reflective surface placed behind the bag.

22. The method claim of claim 19 wherein said at least one interferent in plasma is selected from the group consisting of haemoglobin, bilirubin, biliverdin, equivalent intralipid, and methylene blue.

23. The method of claim 22 wherein absorbance is measured and such measurements are incorporated into the following algorithms for each of haemoglobin, bilirubin, biliverdin, equivalent intralipid, and methylene blue, respectively: