Alanine aminotransferase (ALT) is an enzyme found mostly in the cells of the liver and kidney. Much smaller amounts of it are also found in the heart and muscles. SGPT test measures the level of ALT in the blood.
The function of ALT is to convert alanine, an amino acid found in proteins, into pyruvate, an important intermediate in cellular energy production. In healthy individuals, ALT levels in the blood are low. When the liver is damaged, ALT is released into the blood, usually before more obvious signs of liver damage occur, such as jaundice. This makes SGPT a useful test for early detection of liver damage.
The liver is a vital organ located in the upper right-hand side of the abdominal area, just beneath the rib cage. It is involved in many important functions in the body. The liver helps to process the body's nutrients, manufactures bile to help digest fats, produces many important proteins such as blood clotting factors and albumin, and breaks down potentially toxic substances into harmless ones that the body can use or eliminate.
A number of conditions can cause damage to liver cells, resulting in an increase in ALT. The SGPT test is most useful in detecting damage due to hepatitis or as a result of drugs or other substances that are toxic to the liver.
ALT or SGPT is commonly tested in conjunction with aspartate aminotransferase (AST), another liver enzyme, as part of a liver panel. Both ALT and AST levels usually rise whenever the liver is being damaged, although ALT is more specific for the liver and, in some cases, may be the only one of the two to be increased. An AST/ALT ratio may be calculated to aid in distinguishing between different causes and severity of liver injury and to help distinguish liver injury from damage to heart or muscles.
Liver Injury; Liver Disease; Liver EnzymeDisorder; Jaundice and Hepatitis Viruses.
SGPT test is done to screen for liver damage and/or to help diagnose liver disease. When a healthcare practitioner thinks that you have symptoms of a liver disorder, such as abdominal pain, nausea and vomiting, jaundice (yellow skin), or potential exposure to hepatitis virus; as part of a comprehensive metabolic panel (CMP) when you have a routine health exam.
ALT or SGPT test may be ordered as part of a comprehensive metabolic panel when a person has a routine health examination.
A healthcare practitioner usually orders an ALT test or SGPT test (and several others) to evaluate a person who has signs and symptoms of a liver disorder. Some of these signs and symptoms may include:
Loss of appetite.
Abdominal swelling and/or pain.
Dark urine, light-colored stool.
ALT or SGPT test may also be ordered, either by itself or with other tests, for people who are at an increased risk for liver disease since many people with mild liver damage will have no signs or symptoms. Even without other symptoms, ALT will be increased with mild liver damage. Some examples include:
Persons who have a history of known or possible exposure to hepatitis viruses.
Those who are heavy drinkers.
Individuals whose families have a history of liver disease.
Persons who take drugs that might damage the liver.
Persons who are overweight and/or have diabetes.
When ALT is used to monitor the treatment of people who have liver disease, it may be ordered on a regular basis during the course of treatment to determine whether the therapy is effective.