CPT 82977: Gamma-Glutamyltransferase (GGT) Serum Assay

CPT code 82977 designates a laboratory assay that measures gamma–glutamyltransferase (GGT) in serum. GGT testing is a common biochemical marker used to evaluate liver function and detect injury to the liver or bile ducts; it is also elevated in some primary and metastatic hepatic or biliary cancers. Nationally, GGT testing is an important component of diagnostic workups for hepatobiliary disease and for monitoring patients with suspected cholestasis or hepatotoxic exposure.

Key payers included in the analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise clinical context for CPT code 82977, the typical sites where the service is delivered, and the typical service type. The publication presents benchmarks and policy-relevant observations about lab reimbursement and coverage landscapes, operational considerations for laboratory delivery of the test, and how CPT code 82977 fits into diagnostic pathways for liver and biliary disease.

This summary targets clinicians, laboratory managers, billing professionals, and policy analysts seeking a practical reference for the role and use of CPT code 82977 in clinical practice and payer coverage frameworks. Data not available in the input will be noted where applicable in detailed sections.

Billing Code Overview

CPT code 82977 measures gamma–glutamyltransferase (GGT) activity, typically performed on a serum specimen. The test detects elevated GGT levels associated with liver and biliary tract injury, cholestatic disease, and primary or secondary cancers affecting those regions.

Service type: Clinical laboratory test — biochemical enzyme assay

Typical site of service: Clinical laboratory or hospital outpatient laboratory

Clinical Context

A 56-year-old outpatient presents to a primary care clinic with fatigue, right upper quadrant discomfort, and mildly jaundiced sclera noted on exam. The clinician orders a liver panel including gamma-glutamyltransferase to evaluate hepatobiliary injury and cholestasis. A phlebotomist collects a serum specimen during the clinic visit and sends it to the hospital central laboratory. The clinical laboratory analyst performs 82977 to measure serum gamma–glutamyltransferase (GGT) activity. Results are validated and reported to the ordering provider, who reviews them to support diagnosis of alcohol-related liver injury, biliary obstruction, or hepatic metastasis and to guide further imaging or specialty referral.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional interpretation or oversight portion of a test if split billing applies (rare for automated chemistry tests).
`TC`	Technical component	Use when billing only the laboratory technical component (instrumentation, technician time, reagents).

Taxonomy Code	Specialty	Notes
208D00000X	Pathology	Clinical laboratory directors and pathologists oversee laboratory testing and result interpretation.
207P00000X	Family Medicine	Ordering providers in primary care frequently request GGT testing in initial evaluation of liver dysfunction.
207L00000X	Internal Medicine	Hospitalists and internists commonly order and interpret liver enzyme testing as part of inpatient or outpatient care.
2080P0000X	Clinical Pathology	Laboratory medicine specialists responsible for assay validation and QA/QC for enzymatic assays.
282N00000X	Gastroenterology	Gastroenterologists commonly review GGT results in evaluation of hepatobiliary and pancreatic disease.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`80053`	Comprehensive metabolic panel (CMP)	Often ordered alongside `82977` to evaluate multiple liver enzymes, electrolytes, and renal function in a single panel.
`82043`	Albumin; serum	Albumin is commonly measured with liver panels to assess synthetic liver function when GGT is abnormal.
`84460`	Alanine aminotransferase (ALT)	ALT is paired with GGT to distinguish hepatocellular from cholestatic injury patterns.
`84450`	Aspartate aminotransferase (AST)	AST complements ALT and GGT in evaluating hepatic injury and determining enzyme ratios.
`36415`	Collection of venous blood by venipuncture	Specimen collection procedure required prior to performing `82977` on a serum sample.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`K70.30`	Alcoholic cirrhosis of liver without ascites	Alcohol-related liver disease often elevates GGT; used together with other LFTs to assess hepatic injury.
`K83.1`	Obstruction of bile duct	Biliary obstruction causes cholestatic pattern with elevated GGT to support imaging and intervention decisions.
`K76.9`	Liver disease, unspecified	Non-specific liver enzyme elevations including GGT warrant further evaluation and monitoring.
`C78.7`	Secondary malignant neoplasm of liver and intrahepatic bile duct	Hepatic metastases can impair biliary excretion and elevate GGT; result adds to oncologic assessment.
`E78.5`	Hyperlipidemia, unspecified	Cholestatic enzyme changes may occur with metabolic disease; GGT can be part of cardiovascular risk and metabolic evaluations.

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Summary & Overview