MedicaidCoverageMedium impact
Thiopurine S-Methyltransferase Enzyme Activity Testing - MEDICAID - VIRGINIA (New)
Humana·VA · Gastroenterology, Oncology, Rheumatology +2 more·Pharmacy
Effective date
Jul 22, 2026
We identified it
Jul 23, 2026
Summary
Humana Medicaid Virginia establishes new coverage for TPMT enzyme activity testing (CPT 84433) effective 07/22/2026. The test is covered for two indications: guiding thiopurine medication dosing prior to therapy initiation, or evaluating severe toxicity from thiopurine drugs. Members under 21 require medical necessity review per EPSDT requirements. This is a new policy with no prior guidance superseded.
Action Required
By July 22, 2026: Billing team must update billing system to recognize CPT 84433 as a covered service for Virginia Medicaid members. Configure system to allow claims submission for TPMT testing when documentation supports one of two approved indications: (1) pre-treatment dosing guidance for azathioprine, mercaptopurine, or thioguanine, OR (2) evaluation of severe thiopurine-related toxicity. For members under age 21, flag claims for medical necessity review per EPSDT requirements before submission. Update encounter forms and provider education materials to reflect coverage criteria. Without proper coding and documentation support, claims will be denied.