ABO compatibility testing.pptx...........

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1. drmsaiem ABO COMPATIBILITY TESTING Name:Shanmugham Karthick Raja Group:225B

2. drmsaiem COMPATIBILITY TESTING The cross-match became part of a series of pre-transfusion test known as compatibility testing . The compatibility test includes an ABO and Rh grouping performed on the donor and recipient samples, screening of the donor’s and patient’s sera for unexpected antibodies, and a cross-match. The purpose of pre-transfusion or compatibility testing is to ensure the best possible results of a blood transfusion. The transfused red cells will have an acceptable survival rate, and there will be no significant destruction of the recipient’s own red cells.

3. drmsaiem COMPATIBILITY TESTING Collection and Preparation of Samples . Positive Patient Identification The major cause of transfusion associated fatalities have been clerical errors resulting in incorrect ABO grouping The most common cause of clerical errors and thus transfusion accidents is misidentification of the patient involved in the transfusion. Confusion in identification of the patient when the blood sample was drawn a mixed up samples during handling in the lab, and error in identification of the patient when the transfusion was given.

4. drmsaiem COMPATIBILITY TESTING To prevent collection of samples from the wrong patient , the blood request form must be used to confirm the patient’s identity before phlebotomy is performed . The request form must state the intended recipient’s full name, and unique hospital identification number. Other information such as age and date of birth, address, sex, and name of requesting physician can be used to verify patient identity further but is not required on the form.

5. drmsaiem COMPATIBILITY TESTING Collecting Patient Samples Hemolyzed samples can not be used for testing because hemolysis caused by activation of complement Serum or plasma may be used for pre-transfusion testing. Most blood bank technologist prefer serum because plasma may cause small fibrin clots to form which may difficult to distinguish from true agglutination.

6. drmsaiem COMPATIBILITY TESTING When a specimen is received in the lab, a blood bank technologist must confirm that the information on the sample and requisition form agree. All discrepancies must be resolved before the sample is accepted, and if any doubt exists, a new sample must be drawn.

7. drmsaiem COMPATIBILITY TESTING Donor Samples. Donor testing samples must be taken when the full donor unit is drawn. Depending on the method used for testing, clotted sample, anti-coagulated samples, or both, are obtained. Donor information and medical history card, the pilot samples for processing, and the collection bag must all be labeled with the same unique number code before starting the phlebotomy, and the numbers must be verified again immediately after filling .

8. drmsaiem Compatibility Testing Protocols. Selection of Appropriate Donor Units. In almost all cases, blood and blood components of the patient’s own ABO and Rh group should be selected for transfusion. When blood and blood components of the patient’s type are unavailable or when some other reason precludes their use, units selected must lack any Ag against which the patient has a significant Ab.

9. drmsaiem Selection of Appropriate Donor Units. When transfusion of an ABO group different from the recipient must be given, packed red cells must be used rather than whole blood which contains plasma Abs that are incompatible with the patient’s red blood cells. Group O packed red blood cells can be safely used for all patients, however, conservation of a limited supply of group O blood should dictate its use for patients of other AB types only in special circumstances.

10. drmsaiem Selection of Appropriate Donor Units. If ABO-specific blood is not available or is in less than adequate supply, alternative blood groups are chosen as summarized in the following table; Patient ‘s BG Alternative BG given as packed cells O NONE A O B O AB A, B, O only one of the three should be used for a given patient

11. drmsaiem Selection of Appropriate Donor Units. Rh-negative blood can be given to Rh-positive patients, however, good inventory management again should conserve this limited resource for use in Rh-neg recipients. If Rh-neg units is near expiration, the unit should be given rather than wasted.

12. drmsaiem Testing of the donor sample The transfusing facility is required by AABB standards to confirm the ABO cell grouping on all units and Rh grouping on units labeled Rh-neg. Tests for weak D (D u ) are not required to be reported. The transfusion facility does not need to repeat any other testing procedure.

13. drmsaiem Testing of the patient sample. A record of all results obtained in testing patient samples must be maintained. Identification number should be assigned each time a patient is admitted for treatment. Any discrepancies between previous and current results must be resolved before transfusion is initiated. A new sample should be collected from the patient, if necessary to resolve the problem. ABO and Rh grouping results should be included in the file. Also, notations concerning unusual serologic reactions and the identity of unexpected Abs in the patient’s serum should be included.

14. drmsaiem Testing of the patient sample. ABO and Rh grouping and Ab screening of the patient’s serum can be performed in advance of or at the same time as the cross-match. If the patient has had a transfusion or has been pregnant within the last 3 months or if the history is unavailable or uncertain, the sample must be obtained from the patient within 3 days of scheduled transfusion.

15. drmsaiem Testing of the patient sample. ABO Grouping. Determination of the patient’s correct ABO group is the most critical pre-transfusion serologic test. If the cell and serum grouping results do not agree, additional testing must be conducted to resolve the discrepancy. If the patient’s ABO group cannot be satisfactory determined and immediate transfusion is essential, group O packed red blood cells should be used.

16. drmsaiem Testing of the patient sample. Rh Grouping. Rh grouping is performed using anti-D blood grouping serum. Tube or slide tests should be performed according to the manufacture’s directions for the reagent, which may or may not include the use of a suitable diluents control. Control must be run in parallel with Rh grouping tests performed on patient’s samples, to avoid incorrect designation of Rh neg, patient as Rh positive.

17. drmsaiem Testing of the patient sample. Direct antiglobulin test (DAT) should be performed on the patient’s red blood cells to determine whether uptake of autoantibody, (alloantibodies, if the patient’s has been recently transfused) is responsible for the positive control result.

18. drmsaiem Testing of the patient sample. If the Rh group of the recipient can not be determined and transfusion is essential, Rh negative blood should be given. The test for D u is unnecessary when testing transfusion recipients . Individuals typing as Rh neg in direct testing should receive Rh-neg blood and those typing as Rh pos in direct testing should receive Rh pos blood. As D u are considered Rh pos and may receive Rh pos blood during transfusion.

19. drmsaiem Testing of the patient sample. Antibody Screening. The patient’s serum or plasma must be tested for unexpected Abs. The aim of the Ab screening test is to detect as many clinically significant Abs as possible. Clinically significant Abs refers to Abs that are reactive at 37°C or in the DAT or both and are known to have caused a transfusion reaction or unacceptably short survival of the transfused red blood cells.

20. drmsaiem Testing of the patient sample. Abs Regarded as always being potentially clinically significant ABO Rh Kell Duffy Kidd S s U Abs that may sometime be clinically Significant Le a p Lu a Lu b Cartwright. Abs that rarely, if ever, are clinically significant Le b Chido/Rodgers (Ch a /Rh a ) York, Sd Xg& Bg

21. drmsaiem Testing of the patient sample. Correct ABO grouping results are much more critical to transfusion safety than Ab screening. Most Abs, other than anti-A and anti-B do not cause severe hemolytic transfusion reactions. Thus the vast majority of patients would not suffer grave consequences if transfused with blood from ABO group compatible donor without the benefit of Ab screening tests.

22. drmsaiem Testing of the patient sample. 2- Testing can be performed well in advance of the anticipated transfusion, allowing ample time for identification of unexpected Ab and location of suitable donor units lacking the corresponding Ag. Methods used to detect Abs in patient’s sera must demonstrate all significant coating, hemolyzing, and agglutinating Abs active at 3 7°C.

23. drmsaiem Cross-match The two main functions of the cross-match test can be cited as, I- It is a final check of ABO compatibility between donor and patient. 2- It may detect the presence of an Ab in the patient’s serum that will react with Ags on the donor RBCs but that was not detected in the Ab screening because the corresponding Ag was lacking from the screening cell.

24. drmsaiem Cross-match Antiglobulin Cross-match The procedure begin in the same manner as the IS cross-match, continues to 37°C incubation and finishes with AHG test.

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