We get lots of grouping problems due to weak reverse. When we cannot resolve it at RT we incubate at4Cx60'. This leads to nonspecific reactions due to cold agglutinins.
We set up a cold panel of 3 cell screen, A1 cells, A2 cells, B cells, and auto to find the specificity.
Q1. If everything comes up positive at 4C, how do you resolve this? We call it NTD.
Q2. Is there something else that we can do? We don't want to send samples for Geno?
Q3. If you have to do cold auto adsorption, how do you remove IGM coating the RBC? Same reagents as you use for ZZAP? DTT?
Q4. Most of the time these samples come to our lab for reference testing and we can not reproduce the initial results. The auto control becomes negative. The nonspecific cold agglutinins disappear.
Initially, I thought it's due to cold auto adsorption but the cells are separated from the plasma. Any thoughts, what could be causing this? Antigen sites blocked?
There is a lag of one week between the initial testing and the reference lab testing.