However, the correlation with clinically identified disease status, the concordance of TAA/ABL1 in the marrow and blood of the one evaluable patient, and confirmation of the ddPCR-identified TAAs by flow cytometry in a leukemia cell line, all support the hypothesis that our test measured leukemia burden after HCT and may serve as a biomarker of relapse after HCT. Here, ABL1 is linked to leukemia.