Abnormal LFTs

Based on practical application of guidance from
National Institute for Health and Care Excellence (NICE) and
British Society of Gastroenterology (BSG)

Translated into:

👉 what to actually do when you see abnormal LFTs
👉 in clinic or on call
👉 without over-investigating everyone

Because most abnormal LFTs are benign, but a few are dangerous.

Your job is to tell the difference quickly.

✅ First principle (most important)

Never react to numbers individually.

Always ask:

What pattern is this?

Because management depends on:

  • hepatocellular vs
  • cholestatic vs
  • synthetic failure

Not how high ALT is.

✅ Step 1 – Is the patient sick?

Before any tests:

🚨 Red flags (urgent)

  • Hypotension
  • Confusion
  • Jaundice + fever
  • INR rising
  • Severe abdominal pain
  • Known cirrhosis deteriorating
  • ALT > 1000

👉 Admit / urgent senior review

Do NOT start an outpatient “liver screen”.

This could be:

  • acute liver failure
  • cholangitis
  • severe hepatitis

Emergency, not clinic workup.

✅ Step 2 – Identify the pattern

This decides everything.

🟡 Hepatocellular pattern

ALT/AST ↑↑
ALP normal/mild

Think:
👉 liver cell injury

Common causes:

  • MASLD (fatty liver)
  • alcohol
  • viral hepatitis
  • drugs
  • autoimmune hepatitis

Next step:
👉 blood tests (liver screen)

🟢 Cholestatic pattern

ALP ↑↑
ALT mild

Think:
👉 obstruction

Common causes:

  • gallstones
  • cholangitis
  • malignancy
  • PSC/PBC

Next step:
👉 imaging first (ultrasound)

Not blood tests first.

Very common junior mistake.

🔴 Synthetic dysfunction

INR ↑
Albumin ↓
± bilirubin

Think:
👉 liver failure

Next step:
👉 urgent specialist input

Severity matters more than cause here.

✅ Step 3 – Basic history (often gives diagnosis)

Before ordering anything fancy, ask:

  • Alcohol?
  • BMI/diabetes?
  • New drugs (antibiotics, statins, herbal)?
  • Travel risk?
  • Viral risk factors?
  • Autoimmune disease?
  • Symptoms?

In many patients:
👉 diagnosis is obvious from history alone

✅ Step 4 – First-line investigations

Depends on the pattern.

🟡 If hepatocellular → Liver screen

Order:

  • Hep B & C
  • Autoimmune markers (ANA/ASMA/AMA)
  • Immunoglobulins
  • Ferritin + transferrin saturation
  • Coeliac screen
  • ± ultrasound

Looking for:
👉 viral, autoimmune, iron overload, fatty liver

🟢 If cholestatic → Imaging first

Order:

👉 Ultrasound liver

Looking for:

  • duct dilatation
  • stones
  • masses
  • obstruction

If dilated ducts:
👉 MRCP/ERCP

Blood tests won’t fix an obstruction.

✅ Step 5 – Interpret common results

Normal screen + overweight/diabetic

→ MASLD likely
→ lifestyle advice

Most common real-life answer.

Positive viral markers

→ hepatology referral

ANA/ASMA + high IgG

→ autoimmune hepatitis

AMA + high ALP

→ PBC

Ferritin + high transferrin sat

→ haemochromatosis

Dilated ducts on scan

→ obstruction → urgent referral

✅ Step 6 – Decide who needs referral

Refer routinely if:

  • persistent abnormal LFTs (>3–6 months)
  • positive liver screen
  • suspected chronic liver disease
  • unclear diagnosis

Refer urgently if:

  • obstruction
  • jaundice
  • synthetic failure
  • suspected malignancy
  • decompensation

Don’t refer immediately for:

  • mild ALT 60–80
  • clear MASLD
  • transient illness-related rise

These can be monitored in primary care.

✅ Practical ward/clinic scenarios

Scenario 1

ALT 75, obese diabetic, normal screen
→ MASLD
→ lifestyle

Scenario 2

ALP 500 + jaundice + fever
→ cholangitis
→ urgent imaging/admission

Scenario 3

ALT 300 + positive Hep B
→ viral hepatitis

Scenario 4

Ferritin 900 + transferrin sat 65%
→ haemochromatosis

Scenario 5

Low albumin + INR 2.0
→ liver failure
→ escalate

❌ Common junior mistakes

  • Sending liver screen before imaging in cholestasis
  • Panicking over mild ALT rise
  • Missing medication history
  • Ignoring INR/albumin
  • Referring every mild abnormality
  • Forgetting fatty liver is most common

Be systematic.

✅ Simple NHS pathway (easy memory)

Think:

1️⃣ Sick? → admit
2️⃣ ALT or ALP pattern?
3️⃣ ALT → blood tests
4️⃣ ALP → ultrasound
5️⃣ Synthetic failure → escalate

This covers almost all cases.

✅ Take-home concept

Most abnormal LFTs are fatty liver or alcohol.
Your job is to quickly spot obstruction or liver failure — those are the dangerous ones.

Everything else can usually be outpatient.