Alanine Aminotransferase (ALT)
The enzyme ALT is mainly found in the cells of the liver and in smaller amounts within the kidneys, heart and muscle tissue. If the liver is damaged, blood ALT levels can increase. When the drainage of bile fluid is obstructed, blood ALT levels can also rise.
An small increase in ALT values (approximately 1.5 times the reference value) can occur temporarily from alcohol or certain medications. In this case, it is recommended to repeat the ALT test in a few weeks. If a small increase is found again during a repeat test, or if there are liver-related complaints during the first test, this may indicate liver inflammation, alcohol consumption, drug use, or type 2 diabetes. A larger increase in ALT can be caused by acute liver inflammation such as hepatitis, intake of drugs that are harmful to the liver, or non-alcoholic fatty liver. If the result is more than 5 times greater than the reference value, there is a risk of acute liver damage.
Alkaline Phosphatase (ALP)
Alkaline Phosphatase (ALP) is an enzyme found primarily in the liver, bile ducts, and bones. ALP can also be found in the bones, heart, intestines, placenta, and kidneys. Elevated levels of ALP can indicate damage to any of these areas, particularly the liver or bones. If your test result indicates elevated ALP levels, further tests will be needed to identify the source of the increase.
Gamma-Glutamyltransferase (Gamma-GT)
Gamma-glutamyltransferase (Gamma-GT or GGT) is an enzyme made in the liver that helps convert and digest substances that enter the body through food and drink. Normally the concentration of GGT in the blood is very low, but can become elevated when the liver is overloaded. This happens when the liver must process a high quantity of certain substances in a short period of time, for example with excessive use of certain medications or alcohol. GGT values will also rise when the bile ducts are blocked, with gallbladder problems, or as a result of liver damage. The oral contraceptive pill can cause a decrease in GGT.
Depending on what is causing the rise in liver enzymes, your doctor may advise you to stop drinking alcohol or taking certain medications, lose weight, and/or change your diet.
Bilirubin
Bilirubin is an orange-yellow substance that is created during the normal breakdown of red blood cells. Bilirubin passes through the liver before being excreted from the body. Elevated levels of bilirubin can indicate liver or bile duct problems. Too much bilirubin in the bloodstream can cause jaundice, which causes the eyes and skin to turn yellow.