In this case study, the patient's antibody disappeared from the plasma by adsorbing it into transfused donor red cells. It is detectable but unidentifiable in the post-transfusion red cell eluate.
Several trial-and-error procedures exist to enhance weak antibodies. Depending on its characteristics, which methods will enhance the reactivity of a given antibody?
Methods to investigate weak antibodies include:
- Use a higher plasma-to-red cell ratio (add more antibody-containing plasma or eluate)
- Increase incubation time (if consistent with manufacturer instructions and if applicable)
- Use enzyme-treated panel red cells. Enzymes enhance antigens on RBCs, which change how IgG antibodies interact with those antigens (e.g., Rh and Kidd systems). Enzymes can also denature some antigens (e.g., Fya, Fyb, S).
- Try alternative antibody detection methods. For example, if LISS is used routinely, try polyethylene glycol (PEG) or column agglutination methods such as gel, provided they have been validated in the transfusion services laboratory.
