Quick Review Cards for Medical Laboratory Science

Interpreting Antibody Panels Immunohematology Review 462

Rule out (cross out)

Testing with selected cells

Confirmation

1. On row of ags at top of antigram, cross out those that are present on cells that didn’t react in
   any phase. (Some blood bankers only cross out homozygous ags to avoid missing a weak ab that
   displays dosage.)


2. Circle ags that aren’t crossed out. An ab to 1 or more of these is present.


3. Look for matching patterns, e.g., if serum only reacted with cells # 3 & # 5, & E ag is only on cells #
   3 & # 5, ab is most likely anti-E.
   An ab will react with all cells that possess the corresponding ag (except for abs that demonstrate
   dosage & only react with homozygous cells). An ab won’t react with any cells that lack the correspon-
   ding ag.

If other abs can’t be ruled out, further testing with selected cells might be required. Cells selected

for testing should be pos for only 1 ag corresponding to abs in question, e.g., if pattern of reactivity

matches anti-Jka, but anti-K & anti-S can’t be ruled out, serum should be tested with cells of the

following type:

• Jk(a–), K+, S–


• Jk(a–), K–, S+


• Jk(a+), K–, S–
  Homozygous cells are preferred to avoid missing weak abs that demonstrate dosage.

Conclusive ID requires testing sufficient # of cells that are pos & neg for corresponding ag, e.g., 3 pos &

3 neg. Some labs use other combinations that provide same probability (p) value of£0.05 (i.e., 95%

confidence level that ab ID is correct). Once ab is identified, type pt RBCs for corresponding ag. Should

be neg.