Effective today, Tuesday, December 18, 2018, NPM1 Mutationquantitation by reverse transcription quantitative droplet digital polymerase chain reaction (RT-ddPCR) is available by the Molecular Pathology Laboratory in the Department of Pathology.

Key features to note:

• Testing is to monitor levels of mutant NPM1 transcripts (type A, -TCTG- sequence duplication) during treatment in patients with NPM1-mutated acute myeloid leukemia and assess minimal residual disease (MRD).
• The new assay uses reverse transcription, droplet digital polymerase chain reaction (RT-ddPCR) for quantification of the NPM1 type A (-TCTG- sequence duplication) normalized to ABL1 control gene expression.
• The limit of quantitation is 0.005% NPM1/ABL1 ratio. Positive results less than 0.005% NPM1/ABL1 will be reported as Trace Positive.
• There are minimum ABL1 values for the new assay that must be met to reliably report negative results; values below that will be indicated as an insufficient specimen.

TEST: NPM1 MUTATION QUANTITATIVE, MRD MONITORING AND INTERPRETATION

EPIC Order Code: LAB8828 for peripheral blood and LAB8829 for bone marrow aspirate

Specimen type: Whole blood (EDTA anti-coagulated; 5 mL pink top tube) or bone marrow aspirates (EDTA anti-coagulated; pink or lavender top tube). DO NOT CENTRIFUGE. Store and send whole blood refrigerated.

Method: The NPM1 Mutation Quantitation assay uses multiplex reverse transcription in combination with droplet digital PCR technology. The type A NPM1 duplications occur in most AML cases. The assay can reliably detect 1 tumor cell in a background of 20,000 normal cells. The limit of quantitation is 0.005% IS.

Results Reported: NPM1 Quant % ratio of mutant NPM1 to ABL1 RNA transcript copies.

Questions concerning testing can be directed to Aaron Bossler, MD, PhD (ext. 4-9566, aaron-bossler@uiowa.edu) or Sharathkumar Bhagavathi, MD (ext. 8-8197, sharathkumar-bhagavathi@uiowa.edu).