Increased levels of AST commonly occur with hepatitis, NASH and liver cancer. The highest serum levels occur in viral and toxic hepatitis and ischaemic necrosis. Non hepatic causes include muscular disorders such as polymyositis, acute muscle injury, acute pancreatitis, acute renal failure, acute myocardial infarction and hypothyroidism. AST increase in the absence of ALT indicated cardiac or muscle disease. Minor increases are often transient and benign, and may be related to intercurrent illness, medication use or strenuous exercise.

Analysing the relationship between AST and ALT (AST: ALT ratio) is often useful;  it can be suggestive of certain conditions as there is a considerable overlap. However it is not exclusive and only serves as an aid to clinical decision making. An AST:ALT ratio of > 2:1 is characteristic in patients with alcoholic liver disease. In contrast, viral hepatitis causes ALT to rise more than AST, and the ratio is usually <1, particularly true of hepatitis C.  In Wilson’s disease can cause the AST/ALT ratio to exceed 4.

Transaminases are rarely >10 times the upper limit of normal in uncomplicated alcoholic hepatitis.

Transaminases >20 times can indicate acute viral infection, ischaemic hepatitis, drug or paracetamol toxicity.

Raised AST levels can also occur because of medication, most commonly paracetamol, NSAIDs, ACE-inhibitors, TB treatment (isoniazid), erythromycin and fluconazole.

Please contact us for more information on the reference ranges used at Enfer Medical.