Currentblue cross blue shield - tennesseePolicy N/A

Gamma-Glutamyl Transferase

Defines coverage indications, limitations, reimbursement, and clinical background for serum GGT testing for adult individuals (age 18+) including when GGT testing meets coverage criteria (e.g., elevated alkaline phosphatase, evaluation of liver injury) and when it does not (wellness without abnormal findings).

Policy Summary

Payerblue cross blue shield - tennessee

PolicyGamma-Glutamyl Transferase

Policy CodePolicy N/A

Change TypeAdopted Avalon recommendation

Effective DateN/A

Next Review DateN/A

Key ActionDocument clinical indication(s) (e.g., elevated ALP, chronic alcohol use, hepatotoxin exposure, infections, transplant follow-up, listed diseases) to support medical necessity for GGT testing.

SourceLink

POLICY UPDATE CHANGES

Effective date 7/1/2023 - Adopted Avalon policy recommendation.

1Unit per week reimbursed

AdultsCovered population

1Primary trigger: elevated ALP

1Non-covered: wellness w/o findings

MultipleGuidelines cited

Coverage Summary & Scope

Overview: This policy addresses serum Gamma‑glutamyl transferase (GGT) testing for adult individuals aged >= 18 years. GGT is covered when used to evaluate suspected hepatic causes of abnormal liver tests (for example, to help confirm a hepatic origin of an elevated alkaline phosphatase (ALP)) or to assess liver injury, function, or disease in individuals meeting other listed indications (see policy). GGT testing is not covered when ordered as part of a routine wellness check or general encounters without abnormal findings. Operationally, reimbursement is limited to a maximum of one unit of GGT per week for adults, and repeat testing after a normal result is generally not necessary unless new indications are present per NCD 190.32.

Key Thresholds and Coverage Triggers

Age requirement>= 18 years

Reimbursement frequencyMaximum 1 unit per week

Covered populationAdults only (age 18 and older)

Primary coverage triggerElevated alkaline phosphatase (ALP)

Criteria for Medical Necessity

Medically Necessary / Meets Coverage Criteria

Serum GGT testing meets coverage criteria when the individual is an adult (>=18 years) and meets the following:

ALL of the following

Individual is an adult aged 18 years or olderAge requirement: >= 18 years
NOTE: This policy is intended only for adult individuals aged 18 years and older.
At least one of the following indications
- Elevated alkaline phosphatase activity
- Chronic alcohol or drug ingestion

Not Medically Necessary

Not Medically Necessary / Does Not Meet Coverage Criteria

Situations where serum GGT testing is not covered:

ALL of the following

GGT testing as part of a wellness check or for general encounters without abnormal findings

Documentation, Billing Rules, and Denial Risks

Documentation Required

Indication documentation required

Document clinical indication(s) (e.g., elevated ALP, chronic alcohol use, hepatotoxin exposure, infections, transplant follow-up, listed diseases) to support medical necessity for GGT testing.

Billing Rule

Frequency limit billing rule

Claims should not exceed one unit of GGT reimbursed per adult individual per week; repeat testing after a normal result generally not reimbursed unless new indications are present (per NCD 190.32).

Coding and Regulatory References

No procedure or diagnosis codes provided in this partmixed

No codes listed

Applicable regulatory/coding referencesmixed

No codes listed

Background, Evidence, and Definitions

Background: GGT is a serum enzyme used as a marker of liver dysfunction, bile duct disease, and alcohol consumption and is commonly measured as part of liver function panels. Clinically, GGT measurement is frequently used to help determine whether an elevated ALP is of hepatic origin and may be ordered to evaluate suspected liver injury or as a complementary test in liver panels; it is intended for use in adults (age >= 18 years) per this policy.

Label	Value
ACG recommendation
Before initiating evaluation of abnormal liver chemistries, repeat the lab panel and/or perform a clarifying test (e.g., GGT if serum alkaline phosphatase is elevated). GGT should not be used as a screening test in the absence of other abnormal liver chemistries; elevation of ALP should be confirmed with an elevation in GGT.
NCD 190.32 citation
When used to assess liver dysfunction secondary to existing non-hepatobiliary disease with no change in signs, symptoms, or treatment, it is generally not necessary to repeat a GGT determination after a normal result has been obtained unless new indications are present (CMS NCD 190.32, 2019).
NCD reference
CMS National Coverage Determination for Gamma Glutamyl Transferase (190.32) cited (2019).
Guidelines cited
CAG, ASAM, BSPGHAN, NASPGHAN, EASL, ACG and others cited as supporting various uses of GGT (see guideline sections).

Term	Definition
GGT
Gamma-glutamyl transferase (also GGTP), an enzyme measured in serum to assess liver and biliary disease and alcohol-related liver injury; used to help determine hepatic origin of elevated alkaline phosphatase. Policy applies to adults aged 18 years and older.
LDT
Laboratory-developed test; tests developed and validated in-house by laboratories and regulated under CLIA '88 as high-complexity tests; not FDA approved/cleared for clinical use but may be used when validated.

Medicare Determinations

Number	Name	Type	Effective Date
190.32
Repeat GGT guidance
NCD

190.32
Gamma Glutamyl Transferase
NCD
2019-10

Revision History

7/1/2023adoptionLatest

Effective date 7/1/2023 - Adopted Avalon policy recommendation.

changes

Policy defines coverage indications for serum GGT testing in adults (>=18), including elevated alkaline phosphatase and multiple clinical indications (e.g., chronic alcohol use, hepatotoxin exposure, viral hepatitis, malignancy, diabetes, malnutrition, various systemic diseases) and specifies noncoverage for wellness checks without abnormal findings; reimbursement limited to one unit of GGT per week and repeats after a normal result generally not necessary per NCD 190.32.