Denial Condition

Requests for immune cell function assays (e.g., ImmuKnow™, Pleximmune™, Pleximark™) will be denied because these tests DO NOT MEET COVERAGE CRITERIA. Prior authorization will not render these assays payable.

• Examples: ImmuKnow™, Pleximmune™, Pleximark™

Prior Authorization — Not Applicable

Prior authorization is not a pathway to coverage for immune cell function assays. Because these assays do not meet coverage criteria, submission of a prior authorization request will not result in payment.

Coding and Test Identification

When submitting claims, include the appropriate procedure code and, when applicable, the proprietary test name or laboratory/manufacturer to facilitate claim review.

• Include CPT/HCPCS code (see code group)
• When available, list proprietary test name (e.g., Pleximmune™, Pleximark™, ImmuKnow™) and performing lab/manufacturer

Government Policy Precedence

If there is a conflict between this policy and an applicable government policy (e.g., Medicare LCDs/NCDs or state Medicaid coverage), the government policy prevails and will be used to make the determination. Providers should verify the most up-to-date Medicare and state Medicaid policies.

• Medicare policies: https://www.cms.gov/medicare-coverage-database/search.aspx
• Check applicable state Medicaid websites for state-specific coverage

Documentation Recommendation

Providers should document the clinical indication, relevant diagnostic workup, and how test results would be expected to alter patient management. Maintain documentation of prior screening test results and rationale for any advanced testing.

• Document clinical indication and expected benefit
• Include prior screening test results (e.g., immunoglobulin levels, flow cytometry counts)
• Describe how the assay result would change treatment or management

Stepwise Diagnostic Evaluation

Follow a stepwise diagnostic evaluation for suspected primary immunodeficiency or transplant assessment: start with guideline-recommended screening tests (e.g., flow cytometry to enumerate CD4/CD8 T-cells and NK cells, serum immunoglobulin measurement); abnormal screening results may justify more sophisticated testing. Immune cell function assays are considered advanced/specialized tests and are not covered per this policy.

• Initial/screening tests: flow cytometry (CD4/CD8, NK), serum immunoglobulins, basic lymphocyte subset testing
• Advanced testing: lymphocyte proliferation/mitogen response or other specialized assays only after abnormal screening results
• Policy position: immune cell function assays (examples listed) are not covered