Table 1.

Prerequisites for MRD testing as a basis for treatment decisions

Optimal material	• Material from primary diagnosis (aspirate, biopsy) • Sufficient material and blast content • Selection of correct material (PB/BM)
Skilled laboratory	• Experience (number of ALL cases) • Participation in quality-control rounds • International standards for methods
Reporting of results	• Timely and reliable reporting • Results for each time point should include  ○ Level of MRD  ○ Sensitivity in case of a negative result  ○ Further specification in case of nonquantifiable MRD
Terminology for MRD response	• MRD response is evaluated in patients with hematologic CR • Clear definition of results similar to definition of hematologic CR6,7 MRD CR: ○ MRD-negative with a minimum sensitivity of 0.01% MRD failure: ○ MRD-positive ≥0.01% MRD intermediate: ○ All other types of results, eg, ○ MRD-positive below 0.01% ○ Nonquantifiable but detectable MRD below 0.01% (PNQ) ○ MRD-negative with insufficient sensitivity