Potential reasons for discrepancy between AML MRD testing methods
| Flow cytometry true positive, NGS false negative | AML has no appropriate mutation for tracking (rare) NGS test does not include mutation of interest (common) • Core binding factor leukemia without KIT or other RTK mutation • Complex karyotype AML without TP53 mutation • Chromosomal aneuploidy or structural variants NGS test is insufficient sensitivity/not validated for MRD target (common) |
| NGS true positive, flow cytometry false negative | Lack of target (No LAIP/insufficient DfN) (rare) Limit of detection technique mismatch (eg, NPM1-mutated AML) (common) Heterogeneous or unstable immunophenotype, differentiated cells after therapy (common) |
| NGS false positive, flow cytometry true negative | Technical error (NGS test not validated for MRD use) Inappropriate NGS target selection (eg, isolated DNMT3A mutation) Mutation germ line or present only in cells incapable of causing relapse (eg, lymphocytes) |
| Flow cytometry false positive, NGS true negative | Regeneration after chemotherapy or allogeneic transplant |
| Flow cytometry true positive, NGS false negative | AML has no appropriate mutation for tracking (rare) NGS test does not include mutation of interest (common) • Core binding factor leukemia without KIT or other RTK mutation • Complex karyotype AML without TP53 mutation • Chromosomal aneuploidy or structural variants NGS test is insufficient sensitivity/not validated for MRD target (common) |
| NGS true positive, flow cytometry false negative | Lack of target (No LAIP/insufficient DfN) (rare) Limit of detection technique mismatch (eg, NPM1-mutated AML) (common) Heterogeneous or unstable immunophenotype, differentiated cells after therapy (common) |
| NGS false positive, flow cytometry true negative | Technical error (NGS test not validated for MRD use) Inappropriate NGS target selection (eg, isolated DNMT3A mutation) Mutation germ line or present only in cells incapable of causing relapse (eg, lymphocytes) |
| Flow cytometry false positive, NGS true negative | Regeneration after chemotherapy or allogeneic transplant |
DfN, difference from normal; LAIP, leukemia-associated immunophenotype; RTK, receptor tyrosine kinase.