Documentation and Coverage Requirements

Claims for GGT testing as part of a wellness check or general encounters without abnormal findings will not meet coverage criteria. Document a covered clinical indication (e.g., elevated alkaline phosphatase or one of the listed causes such as chronic alcohol/drug ingestion, hepatotoxin exposure, viral hepatitis, long‑term hepatotoxic drug therapy, malignancy, diabetes, malnutrition, iron/mineral disorders, sarcoidosis, amyloidosis, lupus, hypertension, gastrointestinal or pancreatic disease, or post‑liver transplant assessment). A maximum of one unit of GGT per week will be reimbursed for adults; repeat testing after a normal GGT is generally not necessary unless new indications are present per NCD 190.32.

• Wellness/General Encounter Denial: GGT testing ordered solely as part of a routine wellness visit or without abnormal liver chemistries will be denied.
• Required Clinical Indication: Document the specific clinical reason for testing (e.g., isolated elevated ALP to confirm hepatic origin, signs of liver injury, chronic alcohol use, hepatotoxic exposure, viral hepatitis, post‑transplant evaluation).
• Claim Payment Limit: Reimbursement is limited to one unit of GGT per week for adults.

Government Policy Supersedes

If there is any conflict between this policy and an applicable government policy (e.g., Medicare LCDs or NCDs, or state Medicaid coverage), the government policy supersedes and will be used to make determinations. Providers must follow the most current Medicare and state Medicaid guidance where applicable.

• Government policy supersedes this policy when conflicts exist (e.g., LCDs, NCDs).
• Check CMS Medicare Coverage Database and applicable state Medicaid sites for updates.

Policy Adoption and Effective Date

This policy adopts the Avalon policy recommendation effective 7/1/2023. Reimbursement and utilization review will follow the adopted Avalon criteria; failure to meet the Avalon/adopted policy requirements may result in claim denial or non‑payment.

• Effective date: 2023-07-01 — Avalon policy recommendation adopted.
• Providers should follow any prior authorization or utilization review requirements that derive from the adopted Avalon policy.

Guideline‑Driven Provider Actions Prior to Evaluation

Before initiating evaluation of abnormal liver chemistries, repeat the liver chemistry panel and/or perform a clarifying test (e.g., GGT when ALP is elevated) to confirm the abnormality. When ALP is elevated in isolation, confirm hepatic origin with GGT or ALP fractionation prior to imaging or further workup. If ALP elevation occurs with other abnormal liver chemistries (AST/ALT/bilirubin), confirmation with GGT is not required.

• Guideline‑driven step: For isolated ALP elevation, obtain GGT (or ALP fractionation) to confirm hepatic origin before ordering imaging or hepatology referral.
• Repeat testing: Repeat liver chemistry panel or perform clarifying tests to confirm initial abnormal results prior to additional evaluation.
• When ALP is elevated along with other abnormal liver tests, proceed with evaluation without requiring GGT confirmation.

Specimen and Laboratory Considerations

Serum biomarkers including GGT should preferably be obtained in fasting patients when recommended by the guideline or test manufacturer, and laboratories should follow manufacturer instructions and validation procedures for assays. Clinical literature supports the use of GGT as a complementary test but notes limited specificity — document how results will affect patient management.

• Obtain serum biomarkers (including GGT) preferably in fasting state when indicated by the test or guideline.
• Laboratory‑developed tests (LDTs) for GGT are regulated under CLIA as high‑complexity tests; labs must validate in‑house assays per CLIA requirements.
• Document clinical justification for ordering GGT and how the result will change management given GGT's limited specificity.

Orders must be supported by documented clinical indication

Order should be supported by a documented clinical indication such as elevated ALP or one of the listed clinical conditions; the policy is intended for adult individuals (≥18 years).

No provider-type ordering restrictions stated

The excerpt does not place ordering restrictions by provider type; include GGT in initial evaluation panels typically ordered by clinicians evaluating abnormal liver tests or suspected liver disease per cited guidelines.

GGT may be ordered with panels after abnormal screening or as initial panel

GGT can be ordered as part of liver biochemical panels following abnormal liver screening tests or as part of an initial panel when it is inconvenient for the patient to return for follow-up; ensure order aligns with guideline recommendations.

Order consistent with cited clinical guidelines

Orders for GGT should be consistent with the clinical guidelines cited (e.g., clinicians evaluating abnormal liver tests or suspected cholestasis should follow guideline-recommended testing sequences and documentation).