Detecting residual disease in treated multiple myeloma patients at follow-up
Pathology orders only
The P2 assay is a high-sensitivity assay validated to a sensitivity of 0.01% (1 abnormal plasma cell/10,000 normal cells). This assay is NOT a minimal/measureable residual (MRD) assay, which requires a validated sensitivity of 0.001% (1/100,000). For follow-up of patients who are negative for residual abnormal plasma cells in the P2 assay, we recommend EDTA-anticoagulated bone marrow aspirate be submitted to the Mayo Clinic Laboratories for formal MRD testing (Mayo Clinic Laboratories test code: MRDMM).
Collect 3.0 mL (minimum 1.0mL) bone marrow aspirate in a sodium heparinized syringe and transfer to an anticoagulant free tube.
Bone marrow aspirate:
If you do not use a heparinized syringe to collect the sample:
Dk green Sodium heparin (Na hep), no gel (preferred)
Lavender (EDTA), 4mL (acceptable)
Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times to prevent clotting
Bone marrow core:
RPMI with Hepes/Pen strep/FBS -15 mL
Complete the "Brief clinical information" and "What do you want answered by Flow?" areas on the Flow cytometry requisition
Ambient (preferred) - 72 hours
Frozen - NO
CD19, CD20, CD38, CD45, CD56, IRF4 (nuclear), Kappa (cytoplasmic), Lambda (cytoplasmic) and VS38 (cytoplasmic).