gamma-glutamyl transpeptidase

γ-Glutamyltranspeptidase

Common use

Specimen

Normal findings

Description

This procedure is contraindicated for

N/A

Indications

• Assist in the diagnosis of obstructive jaundice in neonates
• Detect the presence of liver disease
• Evaluate and monitor patients with known or suspected alcohol abuse (levels rise after ingestion of small amounts of alcohol)

Potential diagnosis

Increased in

• GGT is released from any damaged cell in which it is stored, so conditions that affect the liver, kidneys, or pancreas and cause cellular destruction demonstrate elevated GGT levels.

• Cirrhosis
• Diabetes with hypertension
• Hepatitis
• Hepatobiliary tract disorders
• Hepatocellular carcinoma
• Hyperthyroidism (there is a strong association with concurrent liver abnormalities)
• Infectious mononucleosis
• Obstructive liver disease
• Pancreatitis
• Renal transplantation
• Significant alcohol ingestion

Decreased in

Hypothyroidism (related to decreased enzyme production by the liver)

Critical findings

N/A

Interfering factors

• Drugs and substances that may increase GGT levels include acetaminophen, alcohol, aminoglutethimide, anticonvulsants, aurothioglucose, barbiturates, captopril, cetirizine, dactinomycin, dantrolene, dexfenfluramine, estrogens, flucytosine, halothane, labetalol, medroxyprogesterone, meropenem, methyldopa, naproxen, niacin, nortriptyline, oral contraceptives, pegaspargase, phenothiazines, piroxicam, probenecid, rifampin, streptokinase, tocainide, and trifluoperazine.
• Drugs that may decrease GGT levels include clofibrate conjugated estrogens and ursodiol.

Nursing Implications and Procedure

Potential nursing problems

Pretest

• Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
• Patient Teaching: Inform the patient this test can assist in assessing liver function.
• Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
• Obtain a history of the patient’s hepatobiliary system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
• Obtain a history of IV drug use, alcohol use, high-risk sexual activity, and occupational exposure.
• Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
• Review the procedure with the patient. Inform the patient that specimen collection takes approximately 5 to 10 min. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
• Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
• Note that there are no food, fluid, or medication restrictions unless by medical direction.

Intratest

• Potential complications: N/A
• Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
• Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
• Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture.
• Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.
• Promptly transport the specimen to the laboratory for processing and analysis.

Post-Test

• Inform the patient that a report of the results will be sent to the requesting health-care provider (HCP), who will discuss the results with the patient.
• Nutritional Considerations: Increased GGT levels may be associated with liver disease. Dietary recommendations may be indicated and vary depending on the condition and its severity. Currently, there are no specific medications that can be given to cure hepatitis, but elimination of alcohol ingestion and a diet optimized for convalescence are commonly included in the treatment plan. A high-calorie, high-protein, moderate-fat diet with a high fluid intake is often recommended for patients with hepatitis. Treatment of cirrhosis is different because a low-protein diet may be in order if the patient’s liver has lost the ability to process the end products of protein metabolism. A diet of soft foods also may be required if esophageal varices have developed. Ammonia levels may be used to determine whether protein should be added to or reduced from the diet. The patient should be encouraged to eat simple carbohydrates and emulsified fats (as in homogenized milk or eggs) rather than complex carbohydrates (e.g., starch, fiber, and glycogen [animal carbohydrates]) and complex fats, which require additional bile to emulsify them so that they can be used. The cirrhotic patient should also be carefully observed for the development of ascites, in which case fluid and electrolyte balance requires strict attention. The alcoholic patient should be encouraged to avoid alcohol and to seek appropriate counseling for substance abuse.
• Recognize anxiety related to test results, and be supportive of impaired activity related to lack of neuromuscular control, perceived loss of independence, and fear of shortened life expectancy.
• Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.

• Patient Education

  • Educate the patient regarding access to counseling services.
  • Provide teaching and information regarding the clinical implications of the test results, as appropriate.
  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP.
  • Answer any questions or address any concerns voiced by the patient or family.
  • Discuss the implications of abnormal test results on the patient’s lifestyle.
  • Explain to the patient that ongoing fatigue can impact his or her ability to meet personal role performance expectations.
  • Explain that both physical and emotional factors can contribute to fatigue.

• Expected Patient Outcomes

  • Knowledge
  • Validates understanding that chronic fatigue that goes untreated can decrease quality of life
  • Identifies how adequate nutrition may assist to decrease fatigue
  • Skills
  • Independently reviews his or her current list of medications to evaluate if any prescription or nonprescription medications are contributing to fatigue
  • Accurately develops a list of actions that can be taken to reduce fatigue and promote positive health
  • Attitude
  • Complies with the recommendation to obtain a sleep-disorder evaluation to assess for other causes of fatigue
  • Recognizes that both excess and inadequate exercise can contribute to fatigue and makes an effort to pace physical energy expenditures appropriately

Related Monographs

• Related tests include ALT, ALP ammonia, AST, bilirubin, cholangiography percutaneous transhepatic, electrolytes, HAV antibody, HBV antigen and antibody, HCV antibody, hepatobiliary scan, infectious mono screen, KUB studies, liver and spleen scan, MRI liver, TSH, US abdomen, and US liver.
• Refer to the Hepatobiliary System table at the end of the book for related tests by body system.