Uploaded byDr. AJIT SURYA SINGH MD(LABORATORY MEDICINE)
compatabilitytesting....................
This document discusses compatibility testing, also known as pre-transfusion testing. It defines pre-transfusion testing as procedures required to select blood and components that will have acceptable survival when transfused and will not cause destruction of the recipient's red cells. The key steps are proper identification of the recipient's sample, ABO and Rh grouping, screening for irregular antibodies, cross-matching, and selecting a compatible donor. Compatibility testing is divided into pre-analytical, serological, and post-analytical phases. The serological phase includes ABO/Rh grouping, antibody screening and identification, and cross-matching to check for compatibility between the donor's cells and the recipient's serum.
More Related Content
Similar to compatabilitytesting....................
More from Dr. AJIT SURYA SINGH MD(LABORATORY MEDICINE)
compatabilitytesting....................
- 1. COMPATABILITY TESTING ( Pre- Transfusion testing ) 1 By Dr. Ajit Kumar Singh PGT-Laboratory medicine CNCI , Kolkata-700160 Moderator Dr. Rathindra Nath Biswas MD (IH & BT) Assistant Professor Department of laboratory medicine Chittaranjan National Cancer Institute, Kolkata
- 2. Definition 2 “The term Pre-transfusion testing refers to a set of procedures required before blood is issue as being compatible". • The purpose of pre-transfusion testing is to select blood and its component that: They will have acceptable survival when transfused. They will not cause destruction of recipient’s red cells.
- 3. Steps in pre-transfusiontesting 3 1.Proper identification of recipient's ( Patients ) blood sample. 2.Checking the recipient's previous records 3.ABO and Rh grouping of recipient 4.Screening for irregular antibodies with identification 5.Cross matching 6.Selection of ABO & Rh compatible donor, free from blood transmissible infection & irregular antibodies 7.Proper labelling of donor blood
- 4. Compatibility testing dividedin to 3 categories Preanalytical procedure Serological testing Post analytical procedure
- 5. Pre-analytical phase A .Blood requisition form Patient identification (Full name and HUID) Blood component required with quantity Physician name B . Identification of recipient’s blood sample Recipient sample( EDTA/Plain/both) Patient identification Date and time of collection
- 6. Pre-analytical phase Check forthe adequacy of the sample Check for hemolysis
- 7. Serological test ABO/Rh bloodgrouping Screening for irregular antibodies with identification Cross match
- 8. ABO/Rh blood grouping 8 •Determination of ABO type • Determination of Rh D type • Weak D testing is not required to be done on the recipient sample as a part of pre transfusion testing.
- 9. Checking the patientsprevious records If the patient has history of transfusion, his/her previous records must be checked for 1.ABO & Rh blood group 2.Presence of unexpected antibodies 3.Any problems in compatibility testing 4.Any transfusion reactions 9
- 10. Screening of irregularantibodies • The main purpose of screening is for irregular / unexpected antibodies in patient serum • If antibody are detected identification should be perform using panel cells . 10
- 11. Prerequisite for antibodyidentification • Medical history • Age and sex • Medical diagnosis • History of transfusion • In case of female – history of pregnancy, abortion, hydrops etc. • Drug history
- 12. Antibody identification 12 • Identificationof an antibody to red cell antigen requires testing of the recipients serum against a panel of reagent red cells with known antigenic composition. • Each reagent red cell of the panel is from a different donor. • Panel cells should not be use after the expiration date.
- 13.
- 14. 14 Cross match testis carried out to ensure that there are no antibodies present in patients serum that will react with donor cells when transfused. Cross match
- 15. The two mainfunctions of cross match test are 15 1. It is final check of ABO compatibility between the donor and patient 2. It may detect the presence of an antibody in the patient’s serum which will react with an antigen on donor red cells which was not detected in antibody screening because of the absence of corresponding antigen in the screening cells
- 16. 16 • Historically crossmatch testing procedures had been divided into two parts….. • 1.Major cross match • 2.Minor cross
- 17. MINOR CROSS MATCH 17 •PATIENT CELLS + DONOR SERUM
- 18. PRINCIPLE • Minor crossmatchis done to detect any serological incompatibility b/w patient cells and donor serum. • Minor cross match is done with a saline suspension of patients cells and donor serum to look for any complete reactive antibodies 18
- 19. Procedure 19 1.Label the tubeas minor crossmatch with donor number 2.Using a pipette add 1 drops of 5 % patient red cell suspension to the labelled tube 3.Using another pipette add 2 drops of donor’s serum to the same tube 4. Mix the tube well and centrifuge at 1000 RPM for 1 min
- 20. 20 • 5.Gently dislodgethe cell button and observe for agglutination or hemolysis • 6.If there is agglutination or hemolysis , it indicates minor incompatibility • Compatible : NO agglutination or hemolysis • Incompatible : Agglutination or hemolysis seen
- 21. MAJOR CROSS MATCH 21 DONORRED CELLS + PATIENT SERUM
- 22. Principle of majorcross match 22 Major cross match is done to detect any serological incompatibility b/w donor’s cells and patients serum. Major crossmatch is verified with a coombs reaction to detect even the incomplete antibodies.
- 23. Major cross matchTechniques 23 1. Immediate spin method 2. Saline room temperature technique 3. Albumin addition technique 4. Antiglobulin technique
- 24. Major cross matchprocedure 24 1.Put two drops of patients serum in prelabelled test tube 2.Add one drop of 2 – 4% suspension of donor red cells 3.Mix the contents and incubate for 5-10 min for immediate spin method or 40-50 min for saline room temperature technique
- 25. 25 4.Centrifuge the tubesat 1000 RPM for one min. 5.In case of saline room temperature technique , centrifugation is optional 6.Examine the tubes or haemolysis or agglutination 7.If haemolysis or agglutination is present at this stage , the cross- match is incompatible.
- 26. 26 8. If –veno hemolysis or agglutination, wash the cells three to four times with saline and decant the last wash completely . 9. Add one drop of AHG reagent 10. Centrifuge the tubes 1000 RPM for 1 min. 11.Look for agglutination or hemolysis with optical aid. 12.Record the results
- 27. 27 13. If thetest is negative add one drop control IgG coated red cells and centrifuge again at 1000 rpm for 1 min 14. Look for hemolysis or agglutination 15 If no agglutination or hemolysis , the test is invalid repeat the procedure
- 28. Factors Affecting IAT 28 1.Temperature ( 37 oc) 2. Serum : Cell ratio 3. Incubation time 4. Suspending Medium ( sensitivity of IAT increased with addition of 22 % bovine albumin , enzyme or LISS)
- 29. Interpretation 29 • Haemolysis oragglutination at any stage of the test procedure except after adding control IgG coated red cells indicates incompatible
- 30. Post analytical procedures •Proper labelling of donor blood • Issue of blood unit • Return of issued blood unit
- 31.
- 32. Causes of positiveresults in cross- match 32 • 1.Incompatible immediate spin crossmatch with negative antibody screen. Eg ; Incorrect ABO grouping of Pt. & Donor Weak expression of Ag which do not detected on routine serological testing • 2.Positive antibody screen with incompatible AHG crossmatch • 3.Donor red cells with a positive DAT • 4.Problems in pt. serum Eg; Multiple myeloma • 5.Dirty glass ware
- 33. Requirements 33 Materials : 1. 75X 12 mm test tubes 2.Test serum 3.Reagent “o” Positive cells 4.Antiglobulin reagent (AHG) 5.Positive control ( IgG coated red cells) 6.22 % Bovine Albumin 7.Microscope 8.Glass slides 9.Pasteur pipette 10.Centrifuge
- 34. Requirements 34 • 1.Centrifuge • 2.Testtubes • 3.Pasteur pipettes • 4.Normal saline • 5.Glass slides • 6.Microscope