Unformatted text preview: MLS 480 Clinical Immunohematology II Blood Selection/Procedures in Crossmatching (Unit 3) Study Guide Objectives
: At the conclusion of this unit, the student will be able to: 1. Select appropriate donor units based on availability and compatibility. 2. Compare and contrast acceptable criteria for the choice of computer, immediate spin only or complete crossmatch compatibility testing 3. Analyze the possible causes for a crossmatch incompatibility at immediate spin. 4. Analyze the possible causes for a crossmatch incompatibility at the AHG phase 5. Describe the issuing of blood in emergency situations 6. Describe the issuing of blood when group specific blood is not available 7. Illistrate the issuing of blood when Rhtype specific blood is unavailable 8. Evaluate the consequences of massive transfusion 9. Describe the possible causes of negative or positive antibody screen with incompatible crossmatch test results 10. Describe the possible causes of positive antibody screen and compatible crossmatch test results 11. Identify specimen retention requirements in the laboratory 12. Determine the probability of compatible units with single antibody present 13. Determine the purpose for each phase of crossmatch testing 14. Calculate how many donor units are needed to screen for an antigen when more than one unit is requested and the patient has one or more antibodies. 15. Identify the acceptable criteria for use of units unrefrigerated for more than 30 minutes 16. Interpret the expected hgb/hct increase in a patient with a unit of transfused packed cells 17. Interpret the definition of sensitivity and specificity in relation to testing procedures in immunohematology 18. Determine which tests must be performed on a patient’s blood sample before transfusion 19. Determine the testing that must be done on a donor unit being shipped to an institution from another site 20. Describe the testing to be completed on an autoalogous unit 21. Identify the source of the antigen and the antibody in a crossmatch test 22.Identify the maximum amount of time between a patient’s ABO and screen testing and the scheduled transfusion Blood Selection/ Procedures in Crossmatching Study Guide 1. Discuss the possible causes of the following results: Positive antibody screen Incompatible crossmatch Negative auto control 2. In emergency situations, when the patient’s sample has not been obtained but transfusion is critical for patient survival, what is the best choice for donor compatibility? What steps must be taken prior to giving the blood unit, after the unit has left the laboratory? 3. If type specific blood is not available, what is the best course of action in an emergency situation? 4. What tests must be done on the recipient’s blood before transfusion: Obj 18 5. How long must patient’s blood specimen and donor blood specimen be retained: 6. If the patient’s blood is AB and AB blood is not available, what blood should be used: MLS 480 Clinical Immunohematology II
Revision 2013 RP Blood Selection / Procedures in Crossmatching Page 1 of 5 Study Guide 7. How do you calculate the probability of compatible units when the patient has a single antibody: 8. How many units would you have to type (A pos only) to find 2 A pos units that are K and Fya
neg in a white population of donors?: 9. What is the purpose of performing a crossmatch? 10. For each of the following situations, state the ABO/Rh of the blood you would use for transfusion: Patient 1st
Choice Other A pos B pos O neg AB neg 11. The physician has requested blood for surgery for the following patients. He wants to know the likelihood of having blood available for the surgery. You have 10 units of each group specific blood in stock. Answer yes or no for each case below. All antibodies are Coombs reactive: ABO and AB ID of Number of units Yes No Patient requested O pos with antiLea 4 units A pos with antis 2 units O pos with antiJkb 3 units A neg with and K 6 units B pos with antiFya 3 units A pos with and E 2 units 12.
Case Study A A thirtysix year old man was brought to the emergency room after becoming entangled in a piece of farm machinery. Four units of blood were ordered immediately. Results of the ABO typing are given below: AntiA AntiB A Cells B Cells AntiD Rh Control 1 4+ 4+ = = 3+ = Patient’s type First choice for donor Second choice for donor MLS 480 Clinical Immunohematology II
Revision 2013 RP Blood Selection / Procedures in Crossmatching Page 2 of 5 Study Guide 13.
Case Study B A twentytwo year old woman was admitted bleeding heavily from the vagina. Three units of blood were requested uncrossmatched. The blood banker had sufficient time to perform an ABO and Rh typing with the following results: AntiA AntiB A1
Cells B Cells AntiD Rh Control = = 3+ 3+ = = Patient’s type First choice for dono
r Second choice for donor 14.
Case Study C Patient is scheduled for emergency surgery this p.m. The surgeon has ordered 4 units of red cells STAT. The blood bank technologist obtained a sample and proceeds with the routine testing. The results are as follows: AntiA AntiB A1
Cells B Cells AntiD Rh QC Sc I Sc II Sc III = = 4+ 3+ 2+ = = = = Patient’s type First choice for donor Second choice for donor Using the data from Case Study C, answer the following questions: a. What type of blood would you choose for the compatibility test: b. Should you anticipate any problems based on the results of your type and screen: 15. When do you need to do all phases of testing for the crossmatch procedure: 16. If an antibody was previously detected on a patient and is now not evident, what would be the proper course to take if 2 units were ordered on this patient: 17. List the causes of a major crossmatch incompatibility at room temperature: 18. If blood donor units are “checked out” of the blood bank and then returned 30 minutes later unused, what is the proper protocol to follow? 19. Review the effect that one unit of packed cells has on raising the hemoglobin and hematocrit in a patient. MLS 480 Clinical Immunohematology II
Revision 2013 RP Blood Selection / Procedures in Crossmatching Page 3 of 5 Study Guide ●
● 20. Define massive transfusion, discuss the effects, especially if the blood given is not type specific. What considerations must be made regarding coag studies? How much blood loss is considered to be a massive blood loss? 21. List the possible causes for a crossmatch incompatibility at AHG phase: 22. Discuss the following: Antibody screen negative and an incompatible crossmatch test Antibody screen positive and a compatible crossmatch test 23. After patient sample collection what is the maximum amount of time before a new sample of blood is needed for compatibility testing? 24. If the patient is Rh positive, what donor Rh types may be selected? 25. If the patient is Rh positive, what donor Rh types may be selected? 26. How many units would you have to type to find 4 units that are C and K antigen negative? 27. Discuss specificity and sensitivity of the testing in relation to the antibody screen. 28. What testing must be done by the receiving institution of a shipment of donor units from a blood center? 29. What is the purpose of the immediate spin phase in crossmatch testing? 30. What is the purpose of the 37o
phase in crossmatch testing when the patient has an IgG alloantibody? 31. What is the purpose of the AHG phase in crossmatch testing when the patient has an IgG alloantibody? 32. What testing must be performed on an autologous unit? MLS 480 Clinical Immunohematology II
Revision 2013 RP Blood Selection / Procedures in Crossmatching Page 4 of 5 Study Guide 33. Where is the antigen from in the crossmatch test? 34. Where is the antibody from in the crossmatch test? 35. How long can testing be performed before a scheduled transfusion if the patient has either been pregnant or received a transfusion within the last three months? 36. If a recipient is type A and has been given several packed cell units of type O and needs additional units in a few days, what determines if they should revert back to type A units instead of continuing with type O? MLS 480 Clinical Immunohematology II
Revision 2013 RP Blood Selection / Procedures in Crossmatching Page 5 of 5 Study Guide ...
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- Biology, crossmatch test, Crossmatching