400
A crossmatch and screen cells are 2+ at immediate spin, 1+ at 37C, and negative at the IAT phase. Identify the most likely problem.
A- Combination of antibodies
B- Cold antibody(s)
C- Rouleaux
D- Testing error
B- Cold antibody. The pattern fits of a cold reacting at IS phase and of sufficient titer to persist at 37C incubation. The reactions disappear after IAT testing.