GGTP so-called gamma-glutamyltranspeptidase is one of the enzymes used in the diagnosis of liver diseases. What functions does GGTP perform in the body? When should a GGTP test be performed and what is the evidence of an increased GGTP level? Check it out!

What is GGTP?

GGTP( gamma-glutamyltranspeptidase ) is an enzyme that occurs on the cell membranes of cells in many internal organs in the human body. However, the liveris mainly responsible for the production of GGTP . Therefore, the determination of GGTP activity is used to diagnose diseases of the liver and bile ducts.

Determination of GGTP activity in venous blood serum is, along with the enzymes AspAt (aspartate aminotransferase), ALAT (alanine aminotransferase), ALP (alkaline phosphatase) and total bilirubin concentration, the main tool used by doctors to diagnose liver pathology.

GGTP and its features

The GGTP enzyme belongs to the group ofenzymes responsible for the destruction of the peptide bond in long amino acid chains(i.e. peptides, proteins) and their breakdown into smaller parts (as the name suggests it is a peptidase) .

The presence of GGTP is found on the cell membranes of many internal organs of the human body, incl. in:

  • intestines,
  • kidney,
  • pancreas,
  • prostate gland,
  • central nervous system.

However, it is the liver, and more specifically the liver cells, i.e.hepatocytes , are mainly responsible for the production and secretion of the enzyme into the bloodstream.

What is this GGTP test? What are the indications?

Determination of GGTP activity in peripheral blood serum is together with the determination of AST and ALT transaminases as well as alkaline phosphatase and total bilirubin concentrationbasic test of liver function .

All these tests should be ordered at the same time, because a single GGTP measurement alone is not sensitive and specific enough and does not allow the doctor to make a diagnosis.

A panel of liver tests, including GGTP, is performed on patients whose doctor suspects:

  • diseases of the liver parenchyma,
  • alcohol dependence and hence alcoholic liver disease,
  • cancer,
  • cholestasis, or cholestasis, usually caused by cholelithiasis.

The main symptoms reported by patients suffering from diseases of the liver and biliary tract include:

  • pains located in the right subcostal area, occurring mainly after eating a fat-rich meal,
  • yellowish discoloration of the sclera of the eyes (the white part surrounding the iris), skin and mucous membranes
  • abdominal enlargement,
  • generalized itching of the skin,
  • dark-colored urination with discolored, light-colored stools,
  • weight loss despite the lack of a slimming diet,
  • loss of appetite
  • immunity reduction
  • excessive fatigue

Read Also: Liver Research. What tests are carried out in liver diseases?

How to prepare for the GGTP test?

Activity testGGTPlike other liver tests (AspAt, ALT, ALP), should be performed in the morning, on an empty stomach, after a minimum 10 or 12-hour break since the last meal.

To obtain a reliable resultyou should refrain from consuming alcohol and fatty foodson the day before the test.

How is the GGTP test done?

GGTP activity is measured in blood serum. After disinfecting the skin in the area of ​​the elbow fossa, venous blood is collected from the ulnar vein with a sterile disposable needle. After removing the needle, apply pressure to the injection site with a sterile gauze forminimum 10 minutesand do not lift the upper limb upwards to prevent an unsightly bruise.

The GGTP activity test can be performedfree of charge in the medical laboratory upon presentation of a doctor's referral , or for a fee. The cost of a privately commissioned study oscillates around PLN 9.

GGTP test results should be ready for collection on the next business day at the latest.

It is worth noting that even tests performed without a doctor's order, which exceed the upper limit of normal GGTP activity in peripheral blood serum, should be presented to him. After reviewing the patient's clinical condition, the doctor will decide whether further diagnostics are necessary.

Read also: BLOOD: composition and functions

GGTP standards. How to interpret the results?

Each medical laboratory sets its own ranges of GGTP activity standards, which may differ slightly between facilities. For this reason, in order to control the level of the enzyme in the blood serum well and be able to compare with each othertest results, tests should be carried out in the same laboratory.

It is assumed thatnormal GGTP values ​​in women are below 35 IU / L and in men below 40 IU / L.

Increased GGTP is found in people who suffer from:

  • liver diseases, which include diseases of the liver parenchyma, fatty liver, viral hepatitis, toxic, organ damage caused by drug abuse, consumption of poisonous mushrooms or psychoactive and chemical substances, and even cirrhosis,
  • pathologies within the bile ducts that lead to cholestasis; Among them, there are intra- and extrahepatic cholestasis - the most common causes of bile outflow arrest include cholelithiasis and cholelithiasis, cysts within them, as well as neoplastic tumors that cause pressure on the bile ducts and reduce their lumen,
  • primary or metastatic tumor located in the liver,
  • alcoholism, i.e. frequent, uncontrolled, regular alcohol consumption, not necessarily in large amounts,
  • diseases of the pancreas, in particular acute pancreatitis and chronic pancreatitis,
  • autoimmune diseases involving the liver, especially primary sclerosing cholangitis (PSC),
  • rheumatic diseases such as rheumatoid arthritis (RA),
  • coronary artery disease and the state after a previous myocardial infarction,
  • endocrine diseases, especially hyperthyroidism,
  • obesity,
  • diabetes,
  • hyperlipidemia.

Read also: What can fake a blood test result?

What does increased GGTP mean?

It is worth remembering, however, that in some patients, it is estimated thatin about 10 percent. elevated GGTP is isolatedand the cause cannot be found.

On the basis of a single elevated GGTP in the blood serum, the doctor cannot make an unequivocal diagnosis and recognize the disease, because it is not a specific and sensitive test. Furtherdiagnosis is required, with a particular focus onliver disease as these are the most common causes of abnormal test results. A specialist hepatologist deals with liver diseases.

To establish the diagnosis, takea detailed interview , physically examine the patient, order basic biochemical and blood counts, and extend laboratory diagnosticso:

  • determination of the activity of other liver enzymes (AST- aspartate aminotransferase, ALAT- alanine aminotransferase, ALP- alkaline phosphatase)
  • blood bilirubin
  • imaging tests, which of choice is abdominal ultrasound examination (i.e. ultrasound examination of the abdominal cavity)

In addition, it is necessary to exclude infection with the most common hepatitis B and hepatitis C viruses in the population.

The doctor may then decideto have more specialized imaging tests , such as:

  • magnetic resonance imaging,
  • computed tomography,
  • liver elastography,
  • endoscopic diagnosis, depending on the medical condition it considers most likely.

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