41 Antibody Identification (ABID) – Gel Method (G-IAT)

Principle

Antibody Identification (ABID) test performed by Gel  assists with the naming of unexpected blood group antibodies detected in the antibody screening procedure. The addition of a potentiating medium (LISS) helps promote the interaction of red cells allowing antibody/antigen reactions to occur quickly. The antibody(ies) present should explain positive reaction patterns seen on the panel red cells. These reactions are evaluated to identify the antibody(ies) present using an “exclusion” method. Antibody detection does not require enhancement media such as LISS; however, due to time limitations in student labs it is used.

Antibody identification may require an advanced method such as enzyme methods, the procedure for this is the same but note the reagents change. Enzyme panels are supportive information for primary(G-IAT) panels.

Related Policies

This procedure applies to all patient or donor samples that require antibody identification.

Reagents

1. Antibody identification reagent red blood cells and antigram.
   1. 0.8% Panel-antigram
   2. 0.8% Enzyme treated panel
2. Gel Cards (Anti-IgG for G-IAT or Buffered Albumin Gel cards for enzyme)
3. MTS Diluent ( to make auto control, for well 12 on CARD)

Procedure

1. Visually inspect the gel card(s) for dryness, bubbles.
2. In the small block under each gel card well, label the card with numbers 1-11 and auto in space 12. Gel cards have 6 wells, so two cards are required to perform a panel.
   1. Record patient identification and your initials on the white area of the gel card under 1-11 on each card as this assigns the results to the patient.
3. Using an approved pipette Add 50 ul of SUSPENDED 0.8% panel cell 1 to the well labelled 1; be careful not to touch the gel card with the pipette tip, hold straight and steady above the well then dispense into the well without touching the gel card with the pipette tip. With fresh tips, repeat for cells 2 through 11 and auto.
4. Add 25ul of plasma/serum to the wells (1-11 plus auto).
5. Incubate the gel cards according to manufactures directions, at 37 +/- 2 ℃ for 15 minutes.
6. After incubation, centrifuge gel card for 10 minutes.
7. Grade and record results.

Interpretation

1. Agglutination/hemolysis in any phase of testing is a positive test result and indicates the presence of an antigen/antibody reaction. Hemolysis is a positive reaction when using a serum sample with polyspecific AHG.
2. No agglutination/hemolysis of the red cells is a negative test result and may indicate lack of an antigen/antibody reaction.

Notes 

1. If test results with all reagent red cells are reactive, consider the possibilities of an autoantibody, an antibody to high incidence antigen, or an antibody to red cell diluent.
2. Consider reactivity due to dosage effect prior to exclusion of the presence of an antibody.
3. Antibodies to low incidence antigens may be missed because of the absence of the antigen on the panel red cells.
4. Remove the foil from the wells that are to be used; lift the foil to expose the appropriate wells and cut it once wells are open. Leave remaining wells covered to avoid drying out of the gel card.