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National Coverage Determination (NCD)

Gamma Glutamyl Transferase

190.32

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Tracking Information

Publication Number
100-3
Manual Section Number
190.32
Manual Section Title
Gamma Glutamyl Transferase
Version Number
1
Effective Date of this Version
11/25/2002
Ending Effective Date of this Version
Implementation Date
01/01/2003
Implementation QR Modifier Date

Description Information

Benefit Category
Diagnostic Laboratory Tests


Please Note: This may not be an exhaustive list of all applicable Medicare benefit categories for this item or service.

Item/Service Description

Gamma Glutamyl Transferase (GGT) is an intracellular enzyme that appears in blood following leakage from cells. Renal tubules, liver, and pancreas contain high amounts, although the measurement of GGT in serum is almost always used for assessment of hepatobiliary function. Unlike other enzymes which are found in heart, skeletal muscle, and intestinal mucosa as well as liver, the appearance of an elevated level of GGT in serum is almost always the result of liver disease or injury. It is specifically useful to differentiate elevated alkaline phosphatase levels when the source of the alkaline phosphatase increase (bone, liver, or placenta) is unclear. The combination of high alkaline phosphatase and a normal GGT does not, however, rule out liver disease completely.

As well as being a very specific marker of hepatobiliary function, GGT is also a very sensitive marker for hepatocellular damage. Abnormal concentrations typically appear before elevations of other liver enzymes or bilirubin are evident. Obstruction of the biliary tract, viral infection (e.g., hepatitis, mononucleosis), metastatic cancer, exposure to hepatotoxins (e.g., organic solvents, drugs, alcohol), and use of drugs that induce microsomal enzymes in the liver (e.g., cimetidine, barbiturates, phenytoin, and carbamazepine) all can cause a moderate to marked increase in GGT serum concentration. In addition, some drugs can cause or exacerbate liver dysfunction (e.g., atorvastatin, troglitazone, and others as noted in FDA Contraindications and Warnings.)

GGT is useful for diagnosis of liver disease or injury, exclusion of hepatobiliary involvement related to other diseases, and patient management during the resolution of existing disease or following injury.
Indications and Limitations of Coverage

Indications
  1. To provide information about known or suspected hepatobiliary disease, for example:
    1. Following chronic alcohol or drug ingestion.
    2. Following exposure to hepatotoxins.
    3. When using medication known to have a potential for causing liver toxicity (e.g., following the drug manufacturer's recommendations).
    4. Following infection (e.g., viral hepatitis and other specific infections such as amoebiasis, tuberculosis, psittacosis, and similar infections).
  2. To assess liver injury/function following diagnosis of primary or secondary malignant neoplasms.
  3. To assess liver injury/function in a wide variety of disorders and diseases known to cause liver involvement (e.g., diabetes mellitus, malnutrition, disorders of iron and mineral metabolism, sarcoidosis, amyloidosis, lupus, and hypertension).
  4. To assess liver function related to gastrointestinal disease.
  5. To assess liver function related to pancreatic disease.
  6. To assess liver function in patients subsequent to liver transplantation.
  7. To differentiate between the different sources of elevated alkaline phosphatase activity.

Limitations

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.

If the GGT is the only "liver" enzyme abnormally high, it is generally not necessary to pursue further evaluation for liver disease for this specific indication.

When used to determine if other abnormal enzyme tests reflect liver abnormality rather than other tissue, it generally is not necessary to repeat a GGT more than one time per week.

Because of the extreme sensitivity of GGT as a marker for cytochrome oxidase induction or cell membrane permeability, it is generally not useful in monitoring patients with known liver disease.

Note: Scroll down for links to the quarterly Covered Code Lists (including narrative).
Cross Reference

Also see the Medicare Claims Processing Manual Opens in a new window, Chapter 120, Clinical Laboratory Services Based on Negotiated Rulemaking.
Claims Processing Instructions

Transmittal Information

Transmittal Number
17
Coverage Transmittal Link
https://www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/Downloads/R17NCD.pdf Opens in a new window
Revision History

07/2004 - Published NCD in the NCD Manual without change to narrative contained in PM AB-02-110. Coding guidance now published in Medicare Lab NCD Manual. Effective and Implementation dates NA. (TN 17 Opens in a new window) (CR 2130)

07/2002 - Implemented NCD. Effective date 11/25/02.  Implementation date 1/01/03. (TN AB-02-110 Opens in a new window) (CR 2130)
Other

Covered Code Lists (including narrative)

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January 2016 (ICD-10 Opens in a new window)
October 2015 (ICD-10 Opens in a new window, ICD-9 Opens in a new window)
October 2014 (ICD-10 Opens in a new window, ICD-9 Opens in a new window)

Changes to Lab NCD Edit Software

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National Coverage Analyses (NCAs)

This NCD has been or is currently being reviewed under the National Coverage Determination process. The following are existing associations with NCAs, from the National Coverage Analyses database.

Coding Analyses for Labs (CALs)

This NCD has been or is currently being reviewed under the National Coverage Determination process. The following are existing associations with CALs, from the Coding Analyses for Labs database.

Additional Information

Other Versions
Title Version Effective Between View the document version
Gamma Glutamyl Transferase 1 11/25/2002 - N/A You are here
CPT Copyright Statement
CPT only copyright 2002-2011 American Medical Association. All rights reserved. CPT is a registered trademark of the American Medical Association. Applicable FARS/DFARS Apply to Government Use. Fee schedules, relative value units, conversion factors and/or related components are not assigned by the AMA, are not part of CPT, and the AMA is not recommending their use. The AMA does not directly or indirectly practice medicine or dispense medical services. The AMA assumes no liability for data contained or not contained herein.
Reasons for Denial
Note: This section has not been negotiated by the Negotiated RuleMaking Committee. It includes CMS’s interpretation of it’s longstanding policies and is included for informational purposes. Tests for screening purposes that are performed in the absense of signs, symptoms, complaints, or personal history of disease or injury are not covered except as explicity authorized by statue. These include exams required by insurance companies, business establishments, government agencies, or other third parties. Tests that are not reasonable and necessary for the diagnosis or treatment of an illness or injury are not covered according to the statue. Failure to provide documentation of the medical necessity of tests may result in denial of claims. The documentation may include notes documenting relevant signs, symptoms, or abnormal findings that substantiate the medical necessity for ordering the tests. In addition, failure to provide independent verification that the test was ordered by the treating physician (or qualified nonphysician practitioner) through documentation in the physician’s office may result in denial. A claim for a test for which there is a national coverage or local medical review policy will be denied as not reasonable and necessary if it is submitted without an ICD-9-CM code or narrative diagnosis listed as covered in the policy unless other medical documentation justifying the necessity is submitted with the claim. If a national or local policy identifies a frequency expectation, a claim for a test that exceeds that expectation may be denied as not reasonable and necessary, unless it is submitted with documentation justifying increased frequency. Tests that are not ordered by a treating physician or other qualified treating nonphysician practitioner acting within the scope of their license and in compliance with Medicare requirements will be denied as not reasonable and necessary. Failure of the laboratory performing the test to have the appropriate Clinical Laboratory Improvement Act of 1988 (CLIA) certificate for the testing performed will result in denial of claims.
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