A blood test is essential to detect liver damage by determining the presence of liver enzymes in the blood. These liver enzymes normally reside in the liver, but when the liver is injured, these enzymes are spilled into the blood stream. Enzymes help speed up the routine chemical reactions in the body. The body's most widely used liver enzymes are aminotransferase. They contain Alanine Aminotransferase and Asparate.
Aminotransferase enzyme
Liver function tests help determine if a person's liver is functioning properly. It includes measurement of albumin, various liver enzymes such as ALT, AST, ALP and GGT, prothrombin time, total protein and cholesterol.
Alanine Aminotransferase (ALT or SGPT)
When levels of this enzyme are elevated, it shows your liver is under stress or damaged. There are only small traces of these enzymes in skeletal muscles and kidney.
Aspartate Aminotransferase (AST or SGOT)
These enzymes are mostly found in the skeletal muscles, brain, red blood cells and kidney. Elevated levels of ALT do not signal stress or liver damage. However, the presence of high level of AST when high level of ALT is present increases the likelihood of liver stress or damage.
Alkaline Phosphatase (ALP or AP)
This enzyme is found in high concentrations in the bone and liver. It could also be found in the placenta and kidney in small concentrations. It is present in smaller concentrations in the intestine, kidneys and white blood cells. The presence of this enzyme alone does not determine liver damage unless accommodated by other elevated high level enzymes. ALP enzyme metabolizes phosphorus and brings energy to the body.
Gamma Glut amyl Transfarase (GGT)
This enzyme is one of the biggest markers of liver function. It is present abundantly in the liver. GGT and ALP are cholestatic enzymes. If the bile duct is damaged or inflamed, GGT or ALP is spilt from the liver into the blood stream. GGT enzyme is supposed to bring oxygen to the tissues.
| Enzyme | Normal Range |
|---|---|
| ALT | 10-40 U/L |
| AST | 15-50 U/L |
| ALP | 37-116 U/L |
Total protein test measures the amount of protein in the blood. Two main proteins found in the blood are albumin and globulin. Prothrombin is made in the liver, and it helps to clot blood. A prothrombin time test measures the amount of time it takes for a person's blood to clot. Bilirubin is a yellow fluid produced in liver when red blood cells are broken down. If the liver is damaged, bilirubin may leak out from liver into blood stream. When bilirubin builds up, it could also cause jaundice.
It is wise to consult a physician and seek help in understanding the results of a liver test. If any abnormality is found, the doctor would prescribe some medication.