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Order Code CH145
Turnaround Time 24 hours
Test Includes


Specimen Requirements
Specimen Source
Serum, Plasma
Transport Container
(Specimen Container)

SST (Tiger Top) Lithium Heparin/ Sodium Heparin

Preferred Specimens
Minimum Volume (uL)
2.5 uL
Collection Instructions
(Transport Temperature)
Transport Refrigerated (cold packs)
Specimen Stability
Temperature Period
Room temperature 7 days
Refrigerated 7 days
Frozen > 1 year
Test Details
L-Gamma-glutamyl-3-carboxy-4-nitroanilide Substrate
Clinical Significance

Gamma-glutamyl transferase was first identified in kidney tissue. Even though renal tissue has the highest level of GGT, the enzyme present in serum appears to originate primarily from the hepatobiliary system, and GGT is elevated in many forms of liver disease. Elevations in GGT levels are seen earlier and are more pronounced than those with other liver enzymes in cases of obstructive jaundice and metastatic neoplasms. It may reach 5 to 30 times normal levels in intra- or post-hepatic biliary obstruction. Only moderate elevations in the enzyme level (2 to 5 times normal) are observed with infectious hepatitis: therefore, GGT measurements are less useful diagnostically than transaminase determinations with this condition.

Reference Ranges

11 – 59 U/L

8 – 33 U/L