Unit 8 Pretransfusion Testing Part 1

1. Unit 8 Pretransfusion TestingPart 1 Terry Kotrla, MS, MT(ASCP)BB

2. Introduction • Purpose to select for each recipient blood components which when transfused will survive and not cause destruction of recipients rbcs. • Must prevent transfusion of incompatible donor cells which may cause HTR. • US federal government regulates by giving authority to CLIA to oversee testing: • ABO/D • Antibody detection • Antibody identification • Compatibility testing

3. Pretransfusion Testing Requirements • Positive identification of recipient and recipient’s sample. • Review of transfusion records for previous results. • Tests on donor blood. • ABO/D recipient • Antibody detection using serum or plasma • Select ABO/D appropriate components • Test serum/plasma with donor RBCs, i.e., crossmatch • Labeling.

4. Pretransfusion Testing • Transfusion usually safe and beneficial. • Donor or recipient RBCs may undergo accelerated destruction. • Most HEMOLYTIC transfusion reactions caused by errors in patient or sample identity. • Antibody may be below level of detectability. • Even when all done correctly cannot guarantee survival of transfused RBCs.

5. Pretransfusion Testing • If performed PROPERLY testing WILL: • Ensure patient receives correct components. • Verify in most cases components are ABO compatible. • Detect most clinically significant unexpected antibodies.

6. Modern Blood Banking Practices • Many changes over last 20 years. • In 1980’s time for eliminating unnecessary tests. • Ongoing reevaluation led to streamlining procedures for cost effectiveness AND patient safety. • Intelligent approach, requires rigid adherence to guidelines and standards. • Changes based on: • Patient safety • Elimination of unwanted reactions • Increase speed of testing procedures performed.

7. Transfusion Request Form • Can be oral, electronic or written and must include information sufficient to positively ID patient. • Two identifiers required: • Patient full name • Unique ID number • Other identifier • DOB • Driver’s license number • Photographic ID • Blood is a drug and requires physician prescription.

8. Transfusion Request Form • Additional helpful information • Sex • Age • Diagnosis • Transfusion and pregnancy history • Special needs: CMV negative, irradiated, etc. • Reject requisition if • Information is incomplete or lacking. • Inaccurate • Illegible

9. Specimen Requirements • Testing performed only as good as sample submitted. • Properly collected sample from CORRECT patient is CRITICAL to safe blood transfusion. • Patient must be identified with TWO identifiers, best to allow properly trained individuals to collect. • Labeling • Minimum patient full name • Patient unique ID number. • Date and time, although some institutions require date only. • Phlebotomist identification

10. Specimen Requirements • Patient does not have armband physically attached. • DO NOT DRAW • Have qualified healthcare provider band patient. • Emergency protocol must be followed in STAT situations • Emergency room patient identity unknown use temporary ID. • Preadmission testing must stress to patient importance of returning with ID band or will start over. • Sample must be labeled in physical presence of patient.

11. Specimen Requirements • Commercial armbands may be utilized in addition to institution armbands. • Top right: Typenex • Bottom right: Bio-logics.

12. Specimen Requirements • Sample • Draw into stoppered tube • May use serum or EDTA plasma • Can draw from IV line as long as proper protocol followed • Hemolyzed samples should not b used • Samples cannot exceed 3 days if transfused or pregnant last 3 months. • Collection day is day 1, can be used until 11:59pm on day 3. • Sample must represent current immunological status. • No pregnancy or transfusion last 3 months the institution will set requirement for use.

13. Specimen Requirements • Infants less than 4 months old. • No unexpected antibodies detected and infants receive no components containing clinically significant antibodies no additional testing required during neonatal period. • After initial ABO/D type determined this test can be omitted during neonatal period as long as infant receives ABO specific or group O cells with compatible D type.

14. Specimen Requirements • Sample must be verified by qualified laboratory personnel. • Any doubt as to identity of patient or labeling of sample new sample must be obtained. • UNACCEPTABLE and EXTREMELY RISKY to correct incorrectly labeled sample. • Each lab will have policies for accepting mislabeled samples. • Must be able to defend in court reason. • If sample can easily be recollected there should be zero tolerance. • Study found mislabeled samples 40 times more likely to have blood grouping discrepancy.

15. Specimen Requirements - Storage • Sample and sample from donor RBCs (if crossmatch) MUST be stored at 1-6C for SEVEN days AFTER transfusion. • Donor RBCs may be actual segment used for testing. • Donor segment removed upon issuing unit may be saved. • Must have sample for repeat testing if patient has transfusion reaction either immediate or delayed. • Storage capacity will many times determine amount of time sample may be used. • Three day sample plus 7 days = 10 days • For non-pregnant/transfused for last 3 months may elect to use for 14 days + 7 = 21 day storage

16. Previous Records • Compatibility testing MUST include checking previous records for patient’s serological history. • If patient has history must compare current with previous testing. • If discrepancy present MUST resolve. • NOTE: Becoming standard practice to collect SECOND sample after first for patients with no history. • Most significant information is history of clinically significant antibodies • Specificity compared to current antibodies detected. • Regardless of result, may be negative, antigen negative blood MUST be provided.

17. Serological Testing – ABO Grouping • Test unknown RBCs with reagent anti-A and anti-B. • Testing unknown serum with reagent A1 and B cells • Discrepancies MUST be resolved prior to issuing blood. • In an emergency provide • Group O negative RBCs • AB plasma products

18. Serological Testing – D Typing • Test patient and donor RBCs with anti-D. • Tests with anti-D must be controlled to avoid incorrect interpretation. • If problem arises transfuse D negative blood. • Weak D unnecessary for recipients • Donors • No weak D test required at transfusion service. • D typing of D positive donors not required by transfusion service. • Weak D test must be performed by blood collection facility for donors. • If positive labeled “D positive”.

19. Antibody Detection Tests • Serum or plasma tested against single-donor suspension of cells selected to carry blood group antigens necessary for detection of most important CLINICALLY SIGNIFICANT unexpected antibodies. • Unexpected antibodies are those OTHER than anti-A and –B • Clinically significant antibody is/has: • Caused hemolytic disease of the fetus and newborn. • Caused a hemolytic transfusion reaction • Caused unacceptable survival of transfused RBCs • Is reactive at 37C or AHG.

20. Antibody Detection Tests • IgG coated RBCs (check cells) MUST be used to detect false negative antiglobulin tests due to inactivation of Coomb’s serum. • Commercially available screen cells, 2-3 vials, Group O • Following antigens MUST be present: D, C, E, c, e, M, N, S, s, P1, Lea, Leb, K, k, Fya, Fyb, Jka and Jkb. • No requirement for low incidence antigens (Lua, V or Cw) • No requirements for homozygous cells to be present. • May not be used beyond expiration, some antigens deteriorate.

21. Type and Screen • Safe alternative to full crossmatch. • Perform ABO, D and antibody screen. • When done correctly will detect 99.9% of unexpected antibodies. • If antibody screen positive MUST identify antibody and crossmatch antigen negative donors. • If antibody screen negative no crossmatch performed. • Extremely safe and effective. • Most frequently done for obstetrical and pre-operative patients where risk of bleeding is minimal.

22. Type and Screen • If complications arise patient can receive ABO, D type specific immediate-spin crossmatch compatible within 10 minutes. • Transfusion service must have adequate stock of blood.

23. Type and Screen - Limitations • CANNOT detect ALL antibodies • Antibody may be directed against low incident antigen absent from screen cells. • Antibody may have fallen below level of detectability. • Antibody may be exhibiting “dosage” affect, react more strongly with homozygous and weakly or negative with heterozygous.

24. Type and Screen - Limitations • Dosage • RBC which is positive for Jka and Jkb is a heterozygous cell. • Half of the antigens on the RBC will be Jka positive and half will be Jkb positive. • RBC which is positive for Jka and negative for Jkb is assumed to be homozygous for Jka , 100% of the antigens will be Jka . • Example of patient with Jka showing dosage reaction at AHG:

25. References • AABB Technical Manual, 16th edition, 2008 • CAP Today http://tinyurl.com/4cd4qgd • Basic & Applied Concepts in Immunohematology, 2nd edition, 2009 • Ortho WIRE, http://www.ortho-wire.com