Managing raised liver enzymes in asymptomatic patients.(liver function test)

Mr Tony Everitt and Dr Javaid Subhani urge GPs to think carefully before ticking the box for liver function tests in asymptomatic patients

It is common for GPs to tick the liver function test (LFT) box as part of a general health screen. As a consequence, results come back showing abnormal liver enzymes in asymptomatic patient.

This can leave GPs facing a dilemma over whether to conduct further investigations.

A typical LFT profile may consist of total protein, albumin, globulin, total bilirubin, alkaline phosphatase (ALP) and alanine aminotransferase (ALT). Some laboratories may include other tests such as gamma-glutamyltransferase (g-GT) and aspartate aminotransferase (AST).

Standardisation of LFT profiles is likely to be addressed as part of the Government's pathology modernisation programme.

The reference range for a laboratory test is the average value found in a group of healthy subjects +/-2 SD, so 2.5 per cent of results from healthy subjects will be above the reference range and small rises may not be clinically significant. Liver enzyme results in a healthy population also tend to have a skewed distribution, which makes the upper limit of the reference range difficult to define.

Raised alanine aminotransferase

The most common single LFT abnormality is a…