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Test Code LAB4093 GAMMA-GLUTAMYL TRANSFERASE (GGT)

Additional Codes

Labcorp test code 001958

Specimen Type

Preferred Sample:   Lithium Heparin Plasma (PST, Mint Green Tube)
Alternative Sample: Serum (SST, Gold, Corvac, Tiger, Red Top Tube)

Specimen Volume

1 mL

Minimum Volume

0.5 mL

Turnaround Time

STAT: 1 hour

Routine: 4 hours

Sample Stability

Room Temp: 7 days
Refrigerated: 7 days
Frozen: 3 months

Method

Colorimetric

Reference Ranges

Age Range
0 up to 15 days 23 - 219 U/L
15 days up to 1 year 8 - 127 U/L
1 year up to 11 years 6 - 16 U/L
11 years up to 19 years 7 - 21 U/L
19 years and older Male: <55 U/L Female: <38 U/L

 

Reporting Limit

Measuring Range 5 - 1650 U/L

Reporting Limits 5 - 1650 U/L

Synonyms

Gamma- Glutamyl Transferase

CPT Code

82977

 

Limitations

In very rare cases, gammopathy, in particular type IgM (Waldenstrom's Macroglobulinemia), may cause unreliable results.

Clinical Information

Gamma-glutamyl transferase (GGT) is glycoprotein comprised of two subunits. It is located at the cell surface and is highly abundant in luminal surfaces of kidney, biliary system, intestine and epididymis. GGT is encoded by seven different genes, although only one produces an active enzyme that plays an essential role in regulation of oxidative stress, redox signaling and detoxification of xenobiotics through glutathione cleavage.

 

Traditionally, a serum GGT test is used in conjunction with the patient’s history, clinical findings, and additional diagnostic testing for differential diagnosis of hepatobiliary disease (including liver, bile ducts, and gallbladder), intrahepatic or posthepatic biliary obstruction. GGT is also one of the markers for chronic alcoholic liver disease.

 

Elevated levels of GGT were found to be associated with poor outcomes in breast, ovarian, and other types of tumors; increased risk of cardiovascular disease, stroke, and related mortality; pre-disposition to metabolic syndrome and resistance to insulin in type 2 diabetes; chronic kidney disease; and increased iron levels in aging individuals. Accordingly, elevated GGT should not be considered a highly specific marker of hepatobiliary disease.