HEXA Gene Analysis Coding and Billing Guidelines (CM00050, V2)
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October 22, 2015 - Updated 10.13.17

HEXA Gene Analysis Coding and Billing Guidelines (CM00050, V2)

Effective for dates of service on and after February 7, 2013.

The clinical diagnosis of Hexosaminidase A deficiency, a disorder also known as Tay-Sachs disease characterized by progressive weakness, loss of motor skills, and increased startle reflex in infants, relies on blood tests that result in absent or near absent beta-hexosaminidase A (HEX A) enzymatic activity. Molecular genetic testing identifies HEXA gene mutation carriers at risk for conceiving offspring with the disease. Therefore, HEXA genetic testing is not a Medicare benefit and is a statutorily excluded service. In addition to single gene testing, MolDX will also deny panels of tests that include the HEXA gene as a statutorily excluded service.

To receive a HEXA gene test service denial, please submit the following claim information:

  • Select the appropriate CPT code based on type of testing
    • CPT code 81255 – HEXA, common variants
    • CPT code 81406 – HEXA, full gene sequence
  • An Advance Beneficiary Notice of Non-Coverage (ABN)External Website is not required for statutorily excluded services.
    • For a voluntary issued ABN, append with HCPCS modifier GX
    • To indicate a valid ABN is on file for a known statutorily excluded service, append with HCPCS modifier GY
  • Select the appropriate diagnosis for the patient
  • Enter the appropriate DEX Z-code™ identifier adjacent to the CPT code in the comment/narrative field for the following claim field/types:
    • Part A: Line SV202-7 (electronic claim); Block 80 (paper claim)
    • Part B: Loop 2400 or SV101-7 (electronic claim); Box 19 (paper claim)

Reference: Sec. 1862 (1)(A) Statutory Exclusion covers diagnostic testing “except for items and services that are not reasonable and necessary for the diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member,…”

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