Billing and Coding: Genetic Testing for Lynch Syndrome

Coverage for genetic testing for Lynch syndrome follows the clinical and reasonable-and-necessary criteria in LCD L34912. MMR germline testing is expected to follow tumor screening with IHC or MSI, but may be billed with a -KX modifier and supporting documentation when MSI/IHC cannot be performed or yields contradictory results. All claims must be supported by complete, legible medical records that justify the ICD-10 and CPT/HCPCS codes billed and be available upon request.

"Genetic testing for Lynch syndrome is covered when the patient meets the reasonable and necessary clinical criteria specified in LCD L34912."

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