e-learning | Managing abnormal liver function tests

This is a guideline on managing abnormal LFT that was published in 2017 by the British Society of Gastroenterology, but as it so useful I thought it worth summarising it.

Key learning points for me:

  • We should be investigating nearly all abnormal LFTs further and shouldn't use the duration or the degree of the abnormality to decide whether to investigate further.
  • Severe liver disease can present despite normal LFTs.
  • 84% of abnormal LFTs will still be abnormal in 1 months time.
  • 50% of abnormal LFTs found in GP are not further investigated. It is thought that this leads to late presentations for lots of people.
  • 20% of LFTs come back abnormal and less than 10% of these are caused by pre-existing liver disease. So we have our work cut out.

Flow chart advising how to manage a patient with abnormal LFTs

This image is reproduced in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license; click image to go to original.

When we get an abnormal LFT result, what should we do?

Firstly look at the context. Is it a longstanding result? Is the patient well? Is there a known condition or medication contributing.

For example, normal LFT in someone with NAFLD may not be reassuring. It is their risk score that really determines what you do next. Their risk score may still be raised, even with normal LFT.

On the other hand, a patient on a statin with a raised ALT, may not be so concerning as someone who isn't on a statin.

Why can we not be guided by the extent of the derangement?

Many resources have talked about investigating when the ALT reaches 3 x the upper limit of normal and things like that. This guideline wants us to investigate straight away.

The most common causes of significant liver disease are often associated with only mild derangement of LFT. NAFLD is a good example. Ignoring mild changes means that diagnosis is often late, with a worse prognosis.

The current upper levels used for the LFTs, especially for ALT, may actually be too high. It is thought that when they were set, they included a lot of people with occult NAFLD. So results even a bit over the upper level are likely to be significant.

Why can we not be guided by the duration of the derangement?

Only 50% of abnormal LFTs in GP are being followed up. So we're not doing that well really. Delaying things by waiting a couple of months, or doing another normal LFT test before investigating further leads to fewer people being properly investigated.

84% of people with abnormal LFTs will still have abnormal LFTs in a month, so you may as well just investigate straight away. They suggest that you should really only retest just LFT in isolation if you are strongly suspicious of a transient cause.

What further investigations should we do in someone with abnormal LFTs?

Follow the flow chart above.

A standard extended screen would include:

  • Abdo USS.
  • Hep B / C screen.
  • Anti-mitochondrial antibody.
  • Anti-smooth muscle antibody.
  •  Antinuclear antibody.
  • Serum immunoglobulins.
  • Serum ferritin.
  • Transferrin saturation.

Who should we refer?

If a patient has abnormal LFT, even with a negative extended screen and no risk factors for NAFLD, they should be discussed with a gastroenterologist or hepatologist.

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