CD19 and B-cell chronic lymphocytic leukemia: The same group that issued the 2007 ISA approach conducted further studies under the auspices of the European Research Initiative in CLL, and proposed an alternative six-color FLC assay21 that incorporated CD3 into tubes co-stained for CD19/CD5/CD20/CD79b/CD38, demonstrating the importance of removing the group of contaminating CD3+CD19+ that had otherwise been defined as CLL and lowered the positive predictive value of MRD positivity.