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  • Compatibility Testing is a series of procedures designed to ensure the safety of blood for transfusion. Included in the compatibility test is crossmatching which is performed prior to the transfusion of blood components containing red blood cells.
  • Types of crossmatching

    • Major Crossmatch (PS-DR)
    • Minor Crossmatch (PR-DS)
    • Autocontrol (PS-PR)/Direct Coomb's Test
  • Crossmatching

    • It is divided into three kinds: Major Crossmatch, Minor Crossmatch, and Autocontrol/Direct Coomb's Test
  • Compatibility testing is important to ensure the safety of blood for transfusion
  • Crossmatching is performed prior to the transfusion of blood components containing red blood cells
  • Materials/Equipment

    • Wasserman Test tubes
    • Gloves
    • Pasteur pipette
    • Nescofilm
    • Normal Saline Solution
    • Marking pen
    • Gum Label
    • Centrifuge
    • Microscope
    • Agglutination viewer
  • Reagents/Samples

    • 2% - 5% Patient's Red Cell Suspensions
    • 2% - 5% Donor's Red Cell Suspensions
    • Patient's Sera
    • Donor's sera
    • Antihuman globulin sera
    • 22% Bovine Serum Albumin (22% BSA)/Low Ionic Saline Solution (LISS)
  • Pre-Laboratory Activity

    1. Don all your Personal Protective Equipment
    2. Prepare your Workstation by disinfecting it with 70% alcohol or 10% Bleach solution
    3. Put a Laboratory Mat or Plastic cover on your working area, to prevent contamination on the table top
    4. Prepare your Laboratory Materials, Equipment and Worksheet
    5. Put out your reagents on the room temperature
    6. Prepare 2%-5% Red Cell Suspension to your respective donors and recipients
  • Compatibility Testing

    A series of procedures designed to ensure the safety of blood for transfusion
  • Crossmatching

    A procedure performed prior to the transfusion of blood components containing red blood cells
  • Procedures in Protein/Albumin/Room Temperature/Saline/Immediate Spin Phase
    1. Label 4 Wasserman test tubes as M, MA, N, and NA
    2. Add reagents according to the table
    3. Mix the contents and cover the tube with Nescofilm
    4. Centrifuge for 15 seconds at 3400 rpm
    5. Gently dislodge at the cell button and observed for agglutination or hemolysis
    6. If no agglutination or hemolysis is observed, only MA and NA tubes will proceed to the THERMO Phase
  • Procedures in Thermo / Incubation phase (+37°C)
    1. Incubate MA and NA tubes showing no agglutination for 30 minutes (if using LISS, it will be reduced into 15-20 minutes) at +37°C waterbath
    2. Centrifuge for 15 seconds at 3400 rpm
    3. Gently dislodge the cell button and examine for agglutination or hemolysis
    4. If no agglutination or hemolysis is observed in tubes MA or NA, proceed to antihuman globulin phase
  • Procedure in Antihuman Globulin Phase/Coomb's Phase (AHG)
    1. Wash the cells of tubes MA and NA with NSS 3 times
    2. Decant NSS completely after the last wash
    3. Add 2 drops of antihuman globulin sera
    4. Centrifuge for 15 seconds at 3400 rpm
    5. Dislodge the cell button
    6. Add 1 drop of Coomb's check cells to tubes showing no agglutination
  • Compatible

    If there is no agglutination or hemolysis in all tubes in any phases
  • Incompatible

    If there is agglutination or hemolysis in all tubes in any phases
  • Interpretation of Crossmatching Test Results
    • Blood is compatible both in major and minor crossmatching. Blood is safe for transfusion
    • Blood is incompatible in major crossmatch but compatible in minor crossmatch. Blood is not safe for transfusion
    • Blood is incompatible both in major and minor crossmatches. Blood is not safe for transfusion
    • Blood is compatible is major crossmatch but incompatible in minor crossmatch. Blood can be transfused but with caution
  • Red cell phenotyping involves the use of antihuman globulin reagent to detect antigen-antibody complexes
  • IgG antibodies are used to complex with these antigens and who do not readily bring out the agglutination; hence, a Coomb's reagent may be necessary
  • Red Cell Phenotyping may be done through the conventional tube method or gel technology based on the principle of indirect antiglobulin test (IAT)
  • Materials/Equipment for Red Cell Phenotyping
    • Gloves
    • Centrifuge
    • Gum label
    • Wasserman test tubes
    • Nescofilm
    • Marking pen
    • Test tube rack
    • Micropipetor (100 uL – 500 Ul)
    • Water Bath set at +37°C
  • Reagents/Samples for Red Cell Phenotyping
    • Anti-Lea and Anti-Leb reagent sera
    • Anti-Jka and Anti-Jkb reagent sera
    • Anti-Fya and Anti-Fyb reagent sera
    • Normal Saline Solution (0.85-0.90% NaCl)
    • 5% red cell suspension (any ABO type)
  • Procedures for Determination of Lewis Phenotype
    1. Prepare 2 Wasserman Test tubes and Label them as Lea and Leb
    2. Add reagents according to the table
    3. Mix and centrifuge for 15 seconds at 3400 rpm
    4. Gently dislodge and interpret the agglutination reaction. Determine the Lewis Phenotype
  • Procedures for Determination of Kidd Phenotype
    1. Prepare 2 Wasserman Test tubes and Label them as Jka and Jkb
    2. Add reagents according to the table
    3. Mix and centrifuge for 15 seconds at 3400 rpm
    4. Gently dislodge and interpret the agglutination reaction
    5. If there is no agglutination observed on both reaction tubes, incubate them for 5 minutes in a water bath set at +37°C
    6. Centrifuge for 15 seconds at 3400 rpm
    7. Gently dislodge and interpret the agglutination reaction
    8. If there is still no agglutination observed, wash the mixture with NSS three times
    9. On the last washing, completely decant all traces of NSS. Avoid disturbing the intact cell button
    10. Add 2 drops of AHG reagent. Mix and centrifuge for 15 seconds at 3400 rpm
    11. Gently dislodge and interpret the agglutination reaction. Determine the Kidd Phenotype
  • Procedures for Determination of Duffy Phenotype
    1. Prepare 2 Wasserman Test tubes and Label them as Fya and Fyb
    2. Add reagents according to the table
    3. Mix and centrifuge for 15 seconds at 3400 rpm
    4. Gently dislodge and interpret the agglutination reaction
    5. If there is no agglutination observed on both reaction tubes, incubate them for 5 minutes in a water bath set at +37°C
    6. Centrifuge for 15 seconds at 3400 rpm
    7. Gently dislodge and interpret the agglutination reaction
    8. If there is still no agglutination observed, wash the mixture with NSS three times
    9. On the last washing, completely decant all traces of NSS. Avoid disturbing the intact cell button
    10. Add 2 drops of AHG reagent. Mix and centrifuge for 15 seconds at 3400 rpm
    11. Gently dislodge and interpret the agglutination reaction. Determine the Duffy Phenotype
  • Red cell phenotyping is important to identify the antigens on red cells and provide a complete profile of antigens
  • Several antigens are found on red cells and may be potent stimulants of antibody production to individuals who do not possess them
  • Red cell phenotyping is done to detect antigen-antibody complexes using antihuman globulin reagent
  • Agglutination reaction

    Determine Duffy Phenotype
  • Duffy Phenotype
    Determined by the Duffy blood group system
  • Exercise 15.3 Determination of Duffy Phenotype
    1. Record result
    2. Indicate Kidd phenotype of unknown samples
  • Unknown sample X
  • Unknown sample Y
  • Post-Laboratory Activity

    1. Double check reactions
    2. Allow teacher to check work
    3. Return reagents
    4. Clean equipment
    5. Dispose of PPEs
  • Post-Laboratory Questions
    1. Differentiate Lea and Leb
    2. Are anti-Lewis antibodies involved in cases of HDFN and HTR? Justify your answers.
    3. What is the significance of the Kidd Blood Group system in case of delayed type of transfusion reaction?
    4. What is the relevance of Duffy phenotype in malarial parasite transmission?
  • Antibody screening and identification is an application of the concept of indirect antihuman globulin test
  • Purpose of antibody screening and identification
    To detect the immune antibodies that are produced because of antigenic exposure
  • Antibodies are usually IgG and are directed to antigens other than the A and B antigens of the ABO blood group systems
  • The procedure uses panel of O cells whose antigenic profile has been previously identified
  • Lab Exercise 16.1 Antibody Screening
    1. Prepare tubes
    2. Immediate Spin Phase
    3. Incubation phase (+37°C)
    4. Antihuman globulin testing (AHG)
  • Agglutination indicates the presence of atypical antibodies in the patient serum