How to respond to abnormal liver function tests.

disease, so many cases of liver disease are now identified in individuals incidentally found to have abnormal liver function tests (LFTs) as part of routine automated laboratory testing. Abnormal LFTs cannot be ignored because a subgroup of these patients will have progressive and potentially life-threatening liver disease for which therapeutic interventions are often available. Even in an asymptomatic individual a careful history may identify potential causes of abnormal LFTs (Table 1). Clues to covert alcohol abuse include: • loss of licence due to drink driving offences • loss of employment • involuntary separation from partner. History from an independent witness is also valuable where alcohol abuse is suspected. Physical examination is often normal unless hepatomegaly is present – the finding of which lowers the threshold for investigation – or signs indicative of cirrhosis with portal hypertension (splenomegaly, ascites or spider naevi). An appropriate response to abnormal LFTs requires an assessment of: • pattern (hepatocellular or cholestatic) • magnitude of elevation • duration of abnormality • associated symptoms • clinical evidence of cirrhosis. LFT abnormalities fall into several patterns which help in differentiating the underlying liver disease, indicative of: • hepatocellular damage (high serum transaminase) • cholestasis (high alkaline phosphatase (ALP)) • poor synthetic function. Although a liver biopsy is the gold standard for assessing both aetiology and the degree of fibrosis, it is associated with some morbidity and should be undertaken only after assessing the riskbenefit. The clinical setting, together with the specific pattern of LFT abnormality and appropriate additional tests, can narrow the differential diagnosis and provide a cost-effective approach to identifying those patients who need a liver biopsy.