Note: this is an updated version of a previous post.
Anyone reviewing antibody panels, especially in the Middle East/Gulf region, encounters many panels for which no antibody specificity is identified. As a transfusion medicine physician who often got called during the night for release of RBCs for patients with “nonspecific” pattern, this was a big headache.
Is it “nonspecific” because there isn’t a clinically significant antibody OR the technologist did not perform the testing or its interpretation correctly? Does it need further testing? Do I release blood components at this time?
In general, I do not routinely use polyspecific AHG for routine testing. My first choice is for a gamma heavy-chain specific AHG but this is not available for gels or glass beads. Then, I select the IgG AHG even though it does react with light chains and can detect IgM cold antibody reactions.
In general, with nonspecific reactions, I recommend the following:
- Repeat with a gamma heavy-chain specific reagent if the initial workup was made with another type of AHG (polyspecific or whole molecule IgG).
- Always do enzyme panels, sometimes with both papain and ficin reagents: many Rh antibodies are optimally detected only at enzyme (example: R1R1 patient with only anti-E at AHG phase but anti-E and anti-c at enzyme).
- Perform an extended Rh/Kell/Duffy/Kidd/Kell/MNSs/P1 phenotype and specifically check for those negative typing results AND for dosage (could the antibody only be detected in homozygous cells like many anti-M are?).
- Perform classical room temperature, 37C, and finally AHG phase testing. Routinely I do not do this since antibodies not detected at 37C are unlikely to be clinically significant. Sometimes, the AHG phase reactivity is a cold antibody of high-thermal amplitude.
- If the Jka or Jkb antigen typings are negative, repeat using a polyspecific AHG reagent.
- Use additional panels from multiple manufacturers. Some reagents detect more nonspecific reactions than others.
- Try other potentiators than LISS such as PEG.
- Check the outdate of the panel and reagents: if less than 1 week remaining, consider repeating with fresh reagents and getting a new patient sample.
Finally, if you still cannot define the specificity, consider repeating the testing after several days. Maybe it is a newly emerging or an anamnestic response.
I emphasize as a physician, I do not care to see all possible antibodies present in the specimen but rather only those likely to be clinically significant. In general, there is a shortage of labor in the blood banks so I want to eliminate unnecessary work.