Billing and Coding: MolDX: Microsatellite Instability-High (MSI-H) and Mismatch Repair Deficient (dMMR) Biomarker for Patients with Unresectable or Metastatic Solid Tumors

MSI and dMMR testing is covered for patients with unresectable or metastatic solid tumors when testing has not previously been performed, using dMMR by IHC, MSI by PCR, or a multi-gene NGS panel that includes MSI loci and MLH1/MSH2/MSH6/PMS2. NGS assays must be validated to demonstrate >=95% concordance with MSI by PCR, and concurrent use of a multi-gene NGS panel plus a separate MSI PCR will be denied; specified CPT codes (88342/88341 for dMMR, 81301 for MSI, 81479 for NGS) must be submitted.

"Testing for microsatellite instability-high (MSI-H) or mismatch repair deficiency (dMMR) is reasonable and necessary for patients with unresectable or metastatic solid tumors when MSI/dMMR testing ..."

Sign up to see full coverage criteria, indications, and limitations.