Synonym

• Gamma-glutamyl transferase
• Gamma-GT
• GGT
• GGTP
• SGGT

Tubes

• Red, tiger top, or gel barrier tube
• 5 mL of venous blood

Additional information

• 8 hrs fasting before the test
• Handle sample gently to prevent hemolysis
• Send the sample to the lab within 2 hrs

Info

• Gamma-glutamyl transpeptidase (GGT) test measures the concentration of GGT enzyme in the blood
• GGT is a biliary excretory enzyme found mostly in liver, kidneys, and pancreas, with smaller concentrations in lymphocytes, brain, and testes
• GGT assists with reabsorption of amino acids and peptides from the glomerular filtrate and intestinal lumen, and also assists in glutathione metabolism
• GGT is a sensitive indicator of liver cell dysfunction, especially biliary outflow obstruction rather than hepatocellular damage

Clinical

• The clinical utility of GGT includes:
• Evaluation of hepatobiliary disorders
• Assessment of alcohol induced liver disease, and monitoring the progress of therapy as well as alleged abstention from alcohol in known alcoholics
• Assists in differentiation of skeletal and hepatic disorders when serum alkaline phosphatase level is elevated
• GGT can be utilized as a marker for prostatic cancer and hepatic metastasis from breast and colon
• Aids in the differential diagnosis of liver disease in children and pregnant women who have elevated levels of LDH and alkaline phosphatase
• GGT levels remain normal in skeletal diseases
• Treatment of hypertriglyceridemia may lead to decreased GGT levels

Additional information

• GGT is typically twice as high in persons of African ancestry than those of European ancestry
• GGT levels increase with age in women
• Factors interfering with the test results include
• Lipemic sample
• Hemolyzed sample
• Moderate intake of alcohol increases GGT levels for at least 60 hrs
• Presence of high GGT levels in ascitic fluid is suggestive of hepatoma as opposed to cirrhosis or liver metastasis
• Related laboratory tests include:
• 5' nucleotidase
• Alanine aminotransferase
• Alkaline phosphatase and isoenzymes
• Ammonia
• Aspartate aminotransferase
• Bilirubin
• Electrolytes
• Hepatitis A antibody
• Hepatitis B antigen and antibody
• Hepatitis C antibody
• Lactate dehydrogenase (LDH)
• Leucine aminopeptidase (LAP)

Nl Result

Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.

High Result

Conditions associated with elevated GGT levels include:

• Liver diseases
• Cholestasis
• Chronic alcoholic liver disease
• Cirrhosis (familial and obstructive)
• Hepatitis (acute and chronic)
• Infectious mononucleosis
• Liver metastasis and carcinoma
• Pancreatic disease
• Diabetes mellitus
• Myocardial infarction
• Cardiac insufficiency with hepatic congestion
• Congestive heart failure
• Neurologic disorders
• Trauma
• Nephrotic syndrome
• Chronic renal failure
• Chronic obstructive pulmonary disease (COPD)
• Malignancies of
• Breast
• Lung
• Prostate
• Systemic lupus erythematosus (SLE)
• Sepsis
• Glycogen storage diseases
• Hyperthyroidism
• Smoking
• Late pregnancy
• Drugs
• Acetaminophen
• Allopurinol
• Alprazolam
• Amiodarone
• Amphotericin B
• Anastrazole
• Anticonvulsants
• Aurothioglucose
• Azithromycin
• Barbiturates
• Captopril
• Carbamazepine
• Cefdinir
• Cefonicid
• Cefpodoxime
• Ceftazidime
• Cetirizine
• Chloramphenicol
• Chlorpromazine
• Chlorpropamide
• Cimetidine
• Cisplatin
• Clomipramine
• Clozapine
• Cyclosporin A
• Dactinomycin
• Dantrolene
• Diclofenac
• Disopyramide
• Disulfiram
• Doxorubicin
• Doxycycline
• Enalapril
• Esterified estrogens
• Estropipate
• Etoposide
• Etretinate
• Famotidine
• Fluconazole
• Flucytosine
• Fluoxymesterone
• Flutamide
• Fluvastatin
• Fosphenytoin
• Gold
• Griseofulvin
• Haloperidol
• Hepatitis A vaccine
• Hydrochlorothiazide
• Ibuprofen
• Interferon alfa-n3
• Isoniazid
• Isotretinoin
• Isradipine
• Ketamine
• Ketoprofen
• Labetalol
• Lansoprazole
• Levothyroxine
• Lisinopril
• Lomefloxacin
• Loratadine
• Lovastatin
• Medroxyprogesterone
• Meropenem
• Mesalamine
• Methaqualone
• Methotrexate
• Methyldopa
• Metoprolol
• Moexipril
• Mycophenolate
• Nabumetone
• Naproxen
• Nelfinavir
• Nevirapine
• Niacin
• Nicardipine
• Nisoldipine
• Nitrofurantoin
• Nortriptyline
• Octreotide
• Ofloxacin
• Olsalazine
• Omeprazole
• Papaverine
• Pegaspargase
• Phenazopyridine
• Phenobarbital
• Phenothiazines
• Phenytoin
• Piroxicam
• Prazosin
• Probenecid
• Prochlorperazine
• Propafenone
• Propoxyphene
• Quinapril
• Quinidine
• Rifampin
• Riluzole
• Ritonavir
• Sibutramine
• Stanozolol
• Streptokinase
• Sulfamethoxazole
• Sulfasalazine
• Sulfisoxazole
• Sulindac
• Terbinafine
• Thiabendazole
• Thiethylperazine
• Thiopental
• Thioridazine
• Tocainide
• Tolmetin
• Trifluoperazine
• Troglitazone
• Troleandomycin
• Valproic acid
• Warfarin
• Zalcitabine
• Zidovudine

Low Result

Conditions associated with low GGT levels include:

• Hypothyroidism
• Gamma-glutamyl transpeptidase deficiency (autosomal recessive)
• Drugs
• Azathioprine
• Bezafibrate
• Cefotaxime
• Clofibrate
• Conjugated estrogens
• Fenofibrate
• Oral contraceptives
• Ursodiol

References

• Asaba Y et al. Urinary gamma-glutamyltransferase (GGT) as a potential marker of bone resorption. Bone. 2006 Aug 28; [Epub ahead of print].
• Berner MM et al. DOVER and QUVER-new marker combinations to detect and monitor at-risk drinking. Alcohol Clin Exp Res. 2006 Aug;30(8):1372-80.
• Laboratory Corporation of America. Gamma Glutamyl Transpeptidase (GGT). [Homepage on the internet]©2007. Last accessed on April 23, 2007. Available at URL: http://www.labcorp.com/datasets/labcorp/html/chapter/mono/pr004400.htm
• LabTestsOnline®. GGT. [Homepage on the Internet]© 2001-2006. Last reviewed on February 24, 2006. Last accessed on April 23, 2007. Available at URL: http://www.labtestsonline.org/understanding/analytes/ggt/sample.html
• Lee DH et al. Gamma-glutamyltransferase is a predictor of incident diabetes and hypertension: the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Clin Chem. 2003 Aug;49(8):1358-66.
• Li J et al. Follow-up on the gamma-glutamyl transpeptidase in patients with severe dysplasia in an area of high incidence of esophageal cancer. Chin J Dig Dis. 2005;6(3):133-6.
• Morin M et al. gamma-Glutamyl transpeptidase acylation with peptidic substrates: free energy relationships measured by an HPLC kinetic assay. Org Biomol Chem. 2006 Oct 21;4(20):3790-801. Epub 2006 Sep 8.
• UTMB Laboratory Survival Guide®. Gamma Glutamyl Transferase, serum. [Homepage on the Internet]© 2006. Last reviewed in February 2006. Last accessed on April 23, 2007. Available at URL: http://www.utmb.edu/lsg/LabSurvivalGuide/chem/GAMMA_GLUTAMYL_TRANSPEPTIDASE.html
• Yu C et al. Gamma glutamyl transpeptidase is a dynamic indicator of endothelial response to stroke. Exp Neurol. 2006 Sep 12; [Epub ahead of print].