SLIDES ON COMPATIBILITY TESTING -ATU.pptx

Slides on compatibility testing

1. Pre-transfusion COMPATIBILITY TESTING BY MRS. SHEILA ALLOTEY HAEM VI MLH 406 4 TH JUNE, 2024

2. Introduction Pre-transfusion compatibility testing refers to the set of procedures required before blood can be issued as being compatible. It involves the crossmatching of selected donor blood of appropriate ABO and RhD type for a patient requiring a blood transfusion. The donor blood selected is considered compatible if there is no observable reaction in the compatibility tests between the blood of the donor and the blood of the patient. The assumption can then be made that when transfused, the blood will survive normally in the recipient and will cause no adverse reaction.

3. introduction The most important steps during the process are: Correct identification of the patient Checking the patient’s records of previous blood grouping, the presence of any antibodies and details of past transfusions Selecting blood of the correct ABO group for the patient. Crossmatching is a relatively simple process but if not carried out correctly, can lead to the wrong blood being transfused into the patient, with possible disastrous consequences. When this happens it is usually the result of patient misidentification and/or the switching of patient samples, either in the hospital or in the blood bank.

4. Concepts of crossmatching The objective of crossmatching is to carry out the appropriate laboratory tests to provide evidence that blood selected for transfusion into a specific patient should survive normally and benefit that patient without any adverse reaction. There are three types of crossmatching : The major crossmatch The minor crossmatch The electronic crossmatch

5. Major crossmatch I nvolves testing the serum/plasma of the intended recipient with the red cells of the unit of blood selected for transfusion. The major crossmatch is of most value as it tests whether or not the red cells of the blood selected for crossmatching contain antigens against corresponding antibodies in the serum of the recipient. If the crossmatch is positive (signifying a reaction between the donated red cells and recipient antibodies), then the donation is incompatible and that the red cells would be destroyed or have a reduced lifespan if transfused. Major crossmatching involves 3 phases: Phase I: Immediate spin Phase II: Incubation at 37°C Phase III: Indirect antiglobulin test

6. Minor crossmatch It involves testing the red cells of the intended recipient with the plasma unit selected for transfusion. The minor crossmatch is seldom performed unless investigating an adverse reaction to the transfusion of whole blood or plasma products, to determine whether donor plasma contained antibodies directed towards a red cell antigen in the patient. Transfused plasma that is ABO incompatible and of low titre or free of haemolysins , is rapidly diluted in the circulation of the recipient, and may also be neutralized by ABH substances present in a recipient’s tissues, so is unlikely to cause a serious reaction. E.g. Group O plasma transfused to group A recipient .

7. Minor crossmatch Donor plasma may, however, cause reactions in the following circumstances: Donor plasma with potent ABO antibodies may cause a haemolytic reaction. E.g. Strong anti-A,B in group O donor blood may haemolyse the red cells of a group A or B recipient. Donor plasma containing HLA antibodies to recipient white cell antigens may cause transfusion related acute lung injury (TRALI).

8. Electronic crossmatch In electronic crossmatching , a computer program is used to guide the process of checking the critical aspects of compatibility testing: P atient identification M atching of blood groups of intended recipient with blood groups of units selected for transfusion T ransfusion history of the recipient. Red cell units that are ABO and RhD compatible can be quickly issued for a patient on the basis of information in the blood bank information system, with no further testing, provided there are procedures in place to ensure that : The patient’s ABO and RhD type have been tested and also confirmed on a second sample, retested on the first sample, or the patient has been found to be group O in the first instance

9. Electronic crossmatch The patient has no irregular red cell antibodies The grouping of the blood units is fully reliable The identification of the patient and his/her sample is fully reliable The patient’s previous results can be correctly identified and retrieved Electronic issue can take as little as 10 minutes. Hospitals using electronic issue must comply with any applicable national guidelines.

10. critical points • Correct identification of the intended recipient at the time of taking the blood sample for crossmatching . • Checking that the ABO and Rh D type of the recipient is correct. • Checking records to ascertain in the case of repeat transfusions, that the recipient blood grouping results correlate with those on record . • Testing the serum/plasma of the recipient for the presence of irregular and possibly clinically significant irregular antibodies.

11. critical points • Confirmation of ABO group of blood selected for crossmatch , and Rh D group in the case of Rh D-negative recipients. • Crossmatching between serum/plasma of the recipient and red cells of units selected for transfusion. • Correct labelling of crossmatched units that are found compatible and suitable for the recipient. • Checking all details on the request form and component labels at the time of issue and confirmation that the correct blood is being issued for the patient concerned .

12. Patient Identity Wristbands must be worn by patients/recipients of transfusions. A trained and competent phlebotomist, after positively identifying the potential transfusion recipient, should collect a blood sample in a tube. Positive patient identification can be accomplished by requesting the patient to identify him or herself and comparing this information ( 1) to the patient’s identification band and (2) to the request form. If errors in identity are detected, a sample for pre-transfusion testing should not be collected until corrections are done satisfactorily. The sample should be collected only after positive identification is established. Each sample collected is labelled before leaving the patient’s side .

13. Patient Identity The label should be affixed to the tube and contain two unique identifiers, for example, patient’s last and first name, identification number or date of birth and date of collection. The labelled tube is again compared for accuracy to the information on the request form and the patient identification band. The identity of the phlebotomist must also be documented. In an emergency environment, the patient identification may be abbreviated. An individual facility must have a written protocol for establishing patient name and identification number in an emergency.

14. Patient Identification Must confirm recipient’s ID from bracelet ON the patient Full patient name and hospital number Name of physician http://www.usatoday.com/tech/news/techinnovations/2006-07-17-chips-everywhere_x.htm

15. Sample Identification The sample should also have the full patient name, hospital number, and physician Date and time of collection, phlebotomist’s initials All of this should be on the request form and the sample

16. Patient and sample identification Check that the information on the request forms tallies with that on the tube before receiving the sample. The most common cause of error in crossmatching is misidentification of the patient or the sample. This can happen either at the bedside or in the crossmatching laboratory. Reasons for patient/sample misidentification include: Sample taken from the wrong patient (bedside error) Sample labelled with incorrect patient information (bedside error) Wrong sample used for crossmatching (laboratory error) Wrong blood unit selected for labelling (laboratory error) Incorrect unit of blood issued (laboratory error)

17. The Patient Sample Sufficient volume of venous blood should be collected for testing. The correct sample tube must be used. The blood sample submitted for pre-transfusion testing : Should be free from hemolysis. Should not be contaminated with intravenous infusion fluid. Should not be collected in tubes that contain clot activators or other tubes not approved for blood bank use . Every sample should be treated as potentially infectious and appropriate care taken during handling .

18. In the blood bank Samples used for pre-transfusion testing should be collected within 3 days (day of collection is day 0) of the scheduled transfusion if: the patient/recipient has been previously transfused the patient/recipient has been pregnant before. the history is uncertain or unavailable . Recent transfusion and pregnancy are opportunities for sensitization to occur. Sample Retention Samples should be tested as soon as possible after collection. Samples used in testing are stored at 2 ° C to 6°C for a minimum of 7 days.

19. In the blood bank Every request sent to the blood bank should be handled and registered. Every detail on the sample tube label and request form should be checked to ascertain that they correspond correctly . Details should include the following: last name and first name hospital and hospital number ward if applicable age or date of birth date the specimen was taken and name of the phlebotomist signature of requesting clinician.

20. In the blood bank If the request form and sample tube label do not correspond, action should immediately be taken to resolve the problem. The requesting clinician should be asked to submit a new sample and the original should be discarded. Laboratory records should be consulted for documented blood type and transfusion history if the patient has previously received blood. Once the request is accepted, it should be assigned a unique laboratory number to identify the sample and the respective documentation. Patient details should be entered electronically or manually for record and reference purposes. Laboratory personnel should always note the clinical diagnosis provided on the request form on receipt, and ascertain the blood products required, the time required and the reason for blood required.

21. In the blood bank The determination of the patient’s blood group, selection of appropriate blood units and setting up of the compatibility tests, should be undertaken by the same personnel, handling only one request at a time. The sample and request form should be together throughout the process of compatibility testing to ensure that you are working on the correct sample. Ideally, the ABO group on the patient should be performed twice, by two different personnel, The results of the second grouping compared with the first to check that they are the same. If available, the ABO group should then be compared with the patient’s ABO group on record.

22. In the Blood bank If available, the ABO group should then be compared with the patient’s ABO group on record. If any discrepancy is noted, the personnel in charge should immediately be informed and an investigation initiated to resolve the problem. The ABO & Rh D group of the selected blood unit should be checked to ensure that it matches the group label assigned to that unit and compatible with the patient. At the time of blood being issued for transfusion, all details should be carefully checked between blood unit and request form to confirm that they match and that the correct blood is selected for issue, and is compatible

23. Serological Testing Three tests: ABO/Rh D typing Antibody detection/identification Crossmatch

24. ABO/Rh Typing In the ABO typing, the forward and reverse MUST match In the Rh typing, the control(diluent control) must be negative Both of these will indicate what type of blood should be given Tests must be performed according to standard operating procedures.

25. Antibody screen Also called the indirect Coombs test or the indirect antiglobulin test (IAT) The antibody screen will detect the presence of any unexpected antibodies in patient serum. The test should be performed at: Immediate Spin (IS) 37 ° (LISS) AHG using panel of reagent screening cells. If antibodies are detected, identification should be performed using identification cell panel (with an autocontrol ).

26. Crossmatching Purpose : Prevent transfusion reactions Increase in vivo survival of red cells Double checks for ABO errors Another method of detecting antibodies The major crossmatch involves 3 phases: saline ‘immediate spin’ , incubation at 37°C and indirect antiglobulin test (IAT) methods. The immediate spin result is designed to check that blood selected is ABO compatible and to show any incompatibility with an irregular IgM antibody. The same crossmatch test is incubated at 37°C then continued to the IAT phase, to detect any additional incompatibility with IgG antibodies.

27. Emergency Crossmatch The objective is to provide suitable blood quicker, and more cost effectively, without compromising patient safety . ABO and RhD type is performed on patient’s sample and blood units selected. An immediate spin test is performed, using serum/plasma from the patient and cells from the blood units, to check for ABO compatibility. The compatible unit is then issued for transfusion. The incubation and IAT phases of the crossmatch using the donor cells are omitted .

28. Emergency Crossmatch The emergency crossmatch is only suitable if no irregular antibodies have been detected in the patient’s serum/plasma. The antibody screen and IAT crossmatch can be performed in retrospect. When the antibody screen tests are positive or the patient has a history of irregular antibodies of clinical significance, then compatibility testing using the donor cells by IAT must be performed.

29. Crossmatch Donor RBCs (washed) Patient serum No agglutination ~ compatible Agglutination ~ incompatible

30. Electronic crossmatch The electronic or computer matching of blood has been introduced into busy crossmatching laboratories that have the appropriate infrastructure. The donor blood is matched electronically with the patient sample; no serological crossmatch is performed. The sample from the patient must be typed for ABO and RhD group. The serum/plasma must be tested for the presence of IgG antibodies by IAT. If antibody screening tests carried out on the patient are negative, and no anomalous results are obtained in the grouping, and there is no history of irregular antibodies, blood of the same ABO and Rh type can be selected and issued using a validated computer program.

31. Electronic crossmatch In the electronic crossmatch : Only a validated computer system should be used. The ABO group of the patient should be carried out twice. The following details should be captured into the computer program: – at least two details by which the patient may be identified (e.g. name and hospital number ) – ABO and RhD group of patient – P atient antibody screening results – donation number of unit(s) of blood intended for transfusion – type of component intended for transfusion (e.g. red cell concentrate or platelets) – confirmation of blood group of units selected for transfusion.

32. Electronic crossmatch An electronic link between the ABO and RhD group of selected units and the ABO and RhD group of the recipient should be in place to check that they match (are compatible). The computer program should alert the operator to any error, incompatibility or discrepancy . NOTE: This system cannot be used for patients whose serum/plasma have been known to contain a clinically significant red cell alloantibody or the grouping results are equivocal (ambiguous).

33. Selection of blood When ABO group compatible blood is to be used instead of ABO group specific blood, It must be low titre and free of ABO haemolysins . The presence of haemolysins in donor plasma may cause haemolytic reactions in recipients with the corresponding ABO antigens. RhD positive blood should always be selected for RhD positive individuals. Although RhD negative blood may safely be transfused into RhD positive patients, RhD negative units are often in short supply and should be reserved for use in RhD negative patients. In most situations, blood that are nearest to their expiry date should be used first. If a patient is group AB, and group AB donor blood is not available, then group A or B blood may be selected instead, depending on which is more readily available.

34. Selection of blood Patients who type as very weak subgroups of A should receive group O blood. Patients who type as weak AB should receive group B blood. Group AB Rh-positive patients may be referred to as ‘universal recipients’ as they may receive blood from all ABO and RhD groups. In cases of emergency when Rh-negative blood is unavailable, Rh-positive blood may be used for Rh-negative male patients. Rh-positive blood must not be given to Rh-negative female patients of child bearing age. The clinician should take responsibility for the decision to transfuse Rh-positive blood into an Rh-negative recipient.

35. Selection of blood In an attempt to inhibit Rh-immunization in case of accidental transfusion of D+ red cells to a D − patient, anti-D immunoglobulin may be given to the patient immediately after the transfusion to inhibit anti-D formation. This may however, not be a viable option, due to the volume of anti-D required and the prohibitive expense, if the volume of Rh-positive cells transfused is large. When group specific blood is unavailable, group compatible or group O blood may be provided for a patient of another group.

36. Selection of blood If group specific blood then becomes available, it may be considered for use if the number of group compatible/group O units transfused to the patient has not exceeded the prescribed number. A crossmatch should be performed using a fresh sample from the patient to check whether the presence of ABO antibodies in this sample will cause blood of his/her group to be incompatible. If it is incompatible, then group compatible/group O blood should continue to be used. Problems like these are more likely to arise when whole blood is used instead of red cell concentrates, because of the volume of plasma involved.

37. Selection of blood When a massive transfusion has been given, in which the volume of blood transfused within 24 hours equals the estimated blood volume of the patient; continuing to crossmatch further units requested, may not be of value . When authorized by the clinician, further units for transfusion may be retested to check ABO and Rh D group only and issued without crossmatch .

38. Selection blood for neonates and babies When neonates or infants require a normal or exchange transfusion, the freshest blood available preferably not more than 7 days old should be selected. For ‘top-up’ transfusion for anaemia , blood of the same group as the baby or group O of the appropriate Rh group should be selected and matched using the mother’s serum. For exchange transfusion, selection of blood depends on the reason for the exchange. There are 4 reasons for exchange transfusion: Exchange due to Rh D haemolytic disease of the newborn: - Rh D negative blood of the same ABO group as the baby or group O negative should be selected and matched with the mother’s serum.

39. Selection blood for neonates and babies Exchange due to ABO HDN: - Group O blood of the same Rh group as the baby should be selected and matched with the mother’s serum. Exchange due any other cause of neonatal jaundice: - Blood of the same ABO and Rh group as the baby, or group O of the same Rh group should be selected and matched with mother’s serum Exchange due to another Rh antibody (anti-c) or a non-Rh antibody ( anti- Kell ): - Blood that does not have the antigen to the particular antibody of the same ABO group as the baby should be selected and matched with mother’s serum.

40. Standard and emergency situations Approximately 2 hours is required for a standard crossmatch . However, if blood is urgently required, then it may be issued after a direct match (IS) between patient’s serum/plasma and donor’s red cells making blood available in less than 30 minutes. Thereafter , compatibility tests must be completed after the issue of the blood. The hospital personnel must be notified should an incompatibility be detected so that the transfusion may be stopped. If the emergency is such that the prescribing clinician cannot wait for 30 minutes, he/she may take the responsibility for transfusing blood without crossmatch (UNCROSSMATCHED) in which case group O low titre Rh-negative blood should be provided. The blood must be labelled as ‘UNCROSSMATCHED’ and issued as normal .

41. Standard and emergency situations Some hospitals keep small stocks of group O blood for emergency use. It is important that such stocks are controlled by the blood bank, to ensure that they are kept within the correct storage temperature range. Whenever blood is used in emergency situations, it should be crossmatched if possible – if not at the time of transfusion – then as soon as possible thereafter.

42. What can be given in an emergency? Type-Specific, Uncrossmatched Blood The ABO-Rh type Most ABO type-specific transfusions are successful. Caution should be used for patients who have previously received transfusions or have had pregnancies. Type O Rh-Negative (Universal Donor), Uncrossmatched Blood Type O blood lacks the A and B antigens Type O Rh-negative, uncrossmatched packed RBCs should be used in preference to type O Rh-negative whole blood.

43. Compatibility labelling When a unit of blood is compatible with the patient, there must be a way of labelling the unit for the patient. Compatibility labels should be very simple and easy to read so that no mistake can be made when blood is taken from the refrigerator. The compatibility label must have the following: Patient’s name Patient’s hospital number P atient's ward Blood group Expiry date Date of crossmatch .

44. Thank you. Donate blood to save a life. Our blood banks are dry.