Chimerism assay workflow. (A) HLA data readily available for donor(s) and recipient are analyzed. (B) Assay selection is performed. (C) If an informative HLA marker is available, chimerism assays are planned and run using recipient gDNA samples taken after transplant, typically in 2 reference gene replicates and 6 target replicates (all scalable to accommodate more DNA mass) in plate columns from 5 to 12. (D) Actual examples of an HLA-specific and a non-HLA–specific chimerism are provided; chimerism is quantified based on the ratio of a target to a reference quantity, accompanied by a 95% CI of the measurement. (E) If an informative HLA marker is not available, genotyping for 17 non-HLA markers is conducted on donor(s) and recipient samples taken before transplant; our genotyping assays can distinguish the homozygous (+/+) or heterozygous (+/–) presence of an allele based on quantity comparison vs a reference gene; a non-HLA marker is informative if it is positive in the recipient and negative in the donor(s).