Serum transaminases, also known as aminotransferases, are sensitive markers of liver damage and extremely useful in the diagnosis of hepatocellular damage. ALT (SGPT) and AST (SGOT) are the most commonly measurable markers of liver dysfunction.
Transaminases are very useful in identifying the type of liver disease (hepatocellular - cholestatic - mixed) that the gastroenterologist is called upon to investigate. They allow the assessment of the severity of the liver disease and contribute decisively to the prediction of the progression of the disease early on. They are also important in disease monitoring, accurate response to treatment and modification of treatment where necessary.
In general, their values increase in the majority of liver diseases. Common causes of increased transaminases are medications the patient is taking and the presence of fat in the liver. They may be normal in severe disease, such as cirrhosis or hepatocellular carcinoma, while an increase may be seen in non-hepatic conditions, such as due to muscle trauma or heart disease. While they are extremely useful in the differential diagnosis of a liver disease, they rarely lead directly to a definite diagnosis, but usually point towards a general category of liver disease e.g. differential diagnosis of viral from medicinal hepatitis. The range of differential diagnosis in cases of increased transaminases is wide and requires taking a good medical history, a good clinical examination and carrying out further tests depending on the patient's case.