Liver Function Test (LFT)
Liver Function Test is a part of organ profile tests which are the biochemical tests carried out to assess whether the particular organ is functioning properly or not. The levels of various enzymes and protein are checked as a part of liver function test. Liver function test can be used to diagnose problems and disorders related to liver such as liver infections, Hepatitis, Cirrhosis, effects of medications on liver.
Liver function tests include the following:
Alanine Transaminase (ALT) or Serum glutamic pyruvate transaminase (SGPT)
ALT is an enzyme mainly found in liver. High levels of ALT or SGPT in the blood may indicate liver damage. ALT is normally present in the liver and hence it is a specific enzyme for indicating liver injury than AST.
Aspartate Transaminase (AST) or Serum glutamic oxaloacetate transaminase (SGOT)
AST is an enzyme found in quite large amounts in the liver and other parts of the body like muscles.
High levels of AST may be a sign of liver damage. AST levels in blood are also elevated during muscle injury, heart disease such as congestive heart failure and hemolysis.
Alkaline phosphatase (ALP)
ALP is an enzyme mainly present in the liver and bone and is responsible for the breakdown of proteins. High levels of ALP in the blood may indicate liver damage or hepatobiliary disease such as a blocked bile duct, cholangitis or bone diseases.
Gamma-glutamyl transpeptidase (GGT)
GGT is an enzyme found in liver, bile ducts and pancreas. High levels of GGT may be a sign of hepatic or bile duct damage.
Total Protein measures the amount of protein present in the blood. Albumin and Globulin are the two main proteins present in the blood. Albumin and Globulin are produced in the liver. Low albumin and globulin levels can be a sign of liver damage.
Prothrombin is a protein made in the liver and helps in clotting of blood. A high prothrombin time due to lower prothrombin levels can be a sign of liver damage.
Bilirubin is a yellowish pigment present in bile. It is produced during the breakdown of red blood cells. Bilirubin passes through the liver, gets conjugated and is excreted in stool. High levels of bilirubin (jaundice) may be a sign of liver damage or anemia.
Diagnosis based on LFT:
- Hepatitis, fatty liver disease, ischemic hepatitis, autoimmune disorder of liver, hemochromatosis(iron overload), side effect of medications/toxins, Wilson disease(excess copper deposition in the liver, brain and other tissues).
Ms. Yashica Adlakha
Faculty of Biochemistry