Abnormal LFTs Algorithm · Reasoning GP

The full reasoning pathway — pattern first (hepatocellular / cholestatic / isolated bilirubin), screen the NG50 red flags & ≥5× ULN, run the full liver screen even if mildly raised, stage fibrosis (FIB-4), treat the cause, and apply NG12 hepatobiliary 2WW.StartDecisionInvestigateActionReferStop / Admit

PresentationAbnormal liver blood tests

Define the pattern: ALT/AST-dominant (hepatocellular), ALP/GGT-dominant (cholestatic), or isolated bilirubin. Repeat with a split bilirubin. History: alcohol, metabolic syndrome/BMI/T2DM, hepatotoxic drugs, family history.

Step 1 · Safety — NG50 red flagsDecompensation, cancer, or ALT/ALP ≥5× ULN?

Acute liver failure — jaundice + encephalopathy + coagulopathy (↑INR)
Decompensation — ascites, low albumin/platelets, variceal bleed
Suspected malignancy, sepsis, or rapid deterioration
ALT or ALP ≥5× the upper limit of normal

YES — red flag

Stop · escalateAdmit / 2WW hepatology

Acute liver failure → 999. Suspected malignancy / synthetic failure / ≥5× ULN → 2WW or acute medical team.

NO — liver screen

Step 2 · InvestigateFull screen, even if mildly raised

Bilirubin, albumin, ALT, AST, ALP, GGT, FBC, ferritin + transferrin sat; HBsAg + HCV Ab; AMA/ASMA/ANA + immunoglobulins; HbA1c; abdominal USS. Caeruloplasmin if <40.

Step 3 · which pattern?

Hepatocellular (ALT/AST↑)

Liver-cell injury

MASLD/fatty liver (commonest), alcohol, viral hep B/C, drugs, autoimmune, haemochromatosis. AST:ALT >1 suggests advanced fibrosis (>1.5 alcohol). Calculate FIB-4. (ALT also ↑ in thyroid/coeliac/muscle disease.)

Cholestatic (ALP+GGT↑)

Bile-flow problem

Gallstones, stricture, tumour; PBC (AMA), PSC, drugs. Isolated ALP + normal GGT → bone source, not liver.

Isolated bilirubin

Split it

Unconjugated + normal FBC → Gilbert's (reassure). Otherwise exclude haemolysis (retic, LDH, haptoglobin).

Step 7 · treat cause + stage fibrosis

Step 7 · Action — treat the cause, stage the liverModify, stage, monitor

Stop hepatotoxic drugs (recheck); follow the alcohol and MASLD pathways.
MASLD: weight loss, control diabetes/lipids/BP; FIB-4 (± ELF) to stage — low score reassure & recheck, indeterminate/high → hepatology.
Specific disease: antivirals (hep B/C), venesection (haemochromatosis), immunosuppression (autoimmune hepatitis), ursodeoxycholic acid (PBC).
Gilbert's: confirm (total bilirubin <85, conjugated <20%, normal FBC) and reassure — no treatment.

Step 6 · escalation thresholds

Step 6 · ReferEscalation thresholds

Emergency acute liver failure, decompensated cirrhosis, variceal bleed.
2WW · NICE NG12 jaundice aged ≥40 or an upper-abdominal mass → urgent direct-access imaging for suspected pancreatic/hepatobiliary cancer.
Hepatology persistent unexplained derangement, positive liver screen, or significant fibrosis on FIB-4/ELF.

Step 8 · modify & protect

Step 8 · Lifestyle & liver protectionTreat the modifiable drivers

Alcohol reduction/abstinence + brief intervention · weight loss ≥7–10% and exercise for MASLD · optimise diabetes, lipids and BP · hepatitis A/B vaccination in chronic liver disease · review hepatotoxic drugs and supplements · avoid excess paracetamol in established liver disease.

Step 9 · monitor & safety-net

Step 9 · Monitoring & safety-netWhat to recheck, when to return

Recheck LFTs to confirm the trend (e.g. 1–3 months) and repeat FIB-4 periodically. 999 / same-day if jaundice + drowsiness/confusion, bruising/bleeding, vomiting blood, or rapid abdominal swelling. Safety-net: a normalising mild abnormality still needs the cause addressed; escalate persistent or rising results.

⚠️ The number is not the severity: a mildly abnormal LFT panel can hide significant fibrosis. Always pattern-recognise, run the full liver screen even when only mildly raised, and stage fibrosis with FIB-4.

Safety

Red Flags — Exclude Acute Liver Failure & Serious Pathology

Done

Screen immediately for life-threatening causes before any further workup.

Encephalopathy / Confusion Flapping tremor (asterixis), drowsiness, personality change → 999 (acute liver failure)

Jaundice + Fever + RUQ Pain Charcot's triad → 999 (acute cholangitis — Reynold's pentad if shock/confusion)

Coagulopathy INR >1.5, bruising, prolonged bleeding → same-day (acute liver failure, decompensation)

Haematemesis / Melaena Vomiting blood, black stool → 999 (variceal bleed)

Rapid weight loss + jaundice Painless jaundice, anorexia, steatorrhoea → 2WW (pancreatic/cholangiocarcinoma)

Ascites + peripheral oedema New onset, grossly elevated ALT → same-day (decompensated cirrhosis)

Drug-induced (DILI) New drug/supplement started ≤12 weeks, ALT >5× ULN → stop drug, same-day review

Paracetamol overdose Any history of ingestion → 999 (toxicology, N-acetylcysteine window critical)

Acute liver failure (ALF) carries >50% mortality without transplant. The window for intervention is narrow — encephalopathy signals hepatic decompensation. Charcot's triad has >90% specificity for cholangitis, a surgical emergency. Drug-induced liver injury accounts for ~10% of acute hepatitis; stopping the causative agent is curative if caught early. Paracetamol toxicity is treatable within 24h but fatal if missed.

Diagnose

Characterise the Pattern — Hepatocellular vs Cholestatic vs Isolated

Done

Identify the LFT pattern first — this drives your differential and investigations.

Hepatocellular

ALT / AST elevated (>2× ULN, disproportionate to ALP/GGT) → hepatitis, MASLD, alcohol, drugs, autoimmune, Wilson's

Cholestatic

ALP + GGT elevated (disproportionate to ALT) → biliary obstruction, PBC, PSC, drugs, pregnancy

Mixed

All markers elevated → consider drugs, sepsis, infiltrative disease (sarcoid, lymphoma)

Isolated ALP ↑

If GGT normal → likely bone origin (Paget's, puberty, pregnancy) — check isoenzymes or bone profile

Isolated GGT ↑

Alcohol, enzyme-inducing drugs (phenytoin, rifampicin), MASLD — often no serious pathology

ALT:AST ratio

Ratio >2:1 = alcoholic liver disease likely. Ratio <1 = MASLD, viral hepatitis more likely

Bilirubin

Conjugated ↑ = hepatic/biliary pathology. Unconjugated ↑ = haemolysis, Gilbert's (harmless, fasting-related)

Albumin / INR

Low albumin or raised INR = impaired synthetic function → indicates significant hepatic damage

Pattern recognition prevents unnecessary investigation. An isolated GGT in a social drinker rarely warrants liver biopsy, while a cholestatic pattern with ALP 3× ULN needs urgent ultrasound and hepatology input. The ALT:AST ratio (De Ritis ratio) has 70-80% sensitivity for alcoholic liver disease. Gilbert's syndrome affects ~5% of the population and causes benign unconjugated hyperbilirubinaemia — misdiagnosis leads to unnecessary anxiety and investigation.

Diagnose

Targeted History — Systematic Cause Identification

Done

Use a structured history to cover the five main aetiological categories.

Alcohol

AUDIT-C score. Units/week (1 unit = 10ml pure alcohol). Binge pattern. Duration of heavy use. Safe limits: <14u/week

Drugs / Supplements

ALL prescription drugs (statins, methotrexate, amiodarone, antifungals). OTC/herbal (kava, green tea extract). New in last 12 weeks?

Metabolic risk

BMI, T2DM, dyslipidaemia, HTN, PCOS → MASLD screen. Rapid weight loss → acute fatty change

Viral exposure

IV drug use, tattoos, body piercing, blood transfusion (pre-1992), sexual history, travel to endemic regions (HEV)

Autoimmune history

Other autoimmune conditions (thyroid, IBD, coeliac), family history of liver disease, female sex → autoimmune hepatitis

Biliary symptoms

RUQ pain, fat intolerance, pale stools, dark urine, pruritus → cholestatic disease

Family history

Wilson's disease (<40yo), haemochromatosis, alpha-1 antitrypsin deficiency, PBC

Systemic features

Weight loss, night sweats, lymphadenopathy → infiltrative/malignant cause

History identifies the cause in ~70% of cases, before any blood test. MASLD is now the most common cause of incidental LFT derangement in the UK (prevalence ~25% of population). Drugs account for 10% of cases — the temporal relationship (drug started within 12 weeks of LFT rise) is the key diagnostic clue. Wilson's disease is rare but treatable and fatal if missed; screen anyone <40 with unexplained hepatitis.

Diagnose

Targeted Examination — Signs of Chronic Liver Disease

Done

Look for signs of established liver disease, portal hypertension, and metabolic risk factors.

Hands / Nails

Leukonychia (hypoalbuminaemia), clubbing (cirrhosis, IBD), palmar erythema, Dupuytren's (alcohol), asterixis (encephalopathy)

Eyes / Face

Jaundice (scleral icterus), Kayser-Fleischer rings (Wilson's — slit lamp needed), xanthelasma (PBC, dyslipidaemia)

Chest / Abdomen

Spider naevi (>5 = significant), gynaecomastia (alcohol/cirrhosis), hepatomegaly, splenomegaly (portal HTN), ascites (shifting dullness, fluid thrill)

Skin

Jaundice, scratch marks (pruritus = cholestasis), bruising (coagulopathy), parotid enlargement (alcohol)

BMI / Waist

Obesity (BMI >30), central adiposity (waist >88cm F / >102cm M) → MASLD risk factors

Blood pressure

Hypertension + obesity + abnormal LFTs = metabolic syndrome → MASLD pathway

Neurological

Tremor, dysarthria, personality change → Wilson's disease, hepatic encephalopathy

Signs of chronic liver disease (spider naevi, leukonychia, splenomegaly) indicate established cirrhosis and change management significantly — these patients need hepatology referral, variceal screening, and HCC surveillance. Kayser-Fleischer rings (golden-brown corneal deposits) are pathognomonic of Wilson's disease — present in ~95% of neurological Wilson's. Ascites indicates portal hypertension and often requires diuretics and paracentesis — cannot be managed in primary care alone.

Diagnose

Investigations — Systematic Second-Line Bloods & Imaging

Done

Order investigations based on the pattern identified in Step 2. Avoid a 'scattergun' approach.

All cases 1st line

Repeat LFTs in 4-6 weeks if mildly abnormal (<2× ULN). FBC (thrombocytopaenia = portal HTN), U&E, eGFR, glucose, lipids, HbA1c, INR, albumin

Hepatocellular pattern

Hepatitis B sAg + anti-HBc, Hepatitis C Ab, Hepatitis A/E IgM if acute. LFTs >3× ULN: add autoimmune screen (ANA, SMA, anti-LKM1, immunoglobulins)

Cholestatic pattern

AMA (anti-mitochondrial Ab) → PBC. ANCA, p-ANCA → PSC (check with GI). CA 19-9, CEA if malignancy concern

Metabolic/MASLD

Fasting glucose, HbA1c, lipids, TSH, ferritin, transferrin saturation. FibroScan if MASLD confirmed

Alcohol related

GGT (sensitive but non-specific), MCV (macrocytosis), CDT (carbohydrate-deficient transferrin) if occupational/forensic relevance

Genetic / rare

Ferritin + transferrin saturation (haemochromatosis — TS >45%), serum caeruloplasmin (Wilson's <40y), alpha-1 antitrypsin phenotype

Imaging All

Liver ultrasound: structural causes (gallstones, biliary obstruction, fatty infiltration, masses, cirrhotic texture, splenomegaly)

When NOT to investigate

Isolated GGT mildly ↑ in known social drinker with no other features — repeat after 4/52 abstinence. Isolated ALP ↑ in pregnancy (placental isoenzyme) — normal finding

NICE CG165 (2016) recommends a targeted approach. Liver ultrasound is the first-line imaging modality (sensitivity 80-90% for hepatic steatosis, >95% for biliary dilation). FibroScan (transient elastography) quantifies liver stiffness non-invasively — kPa >8 suggests significant fibrosis, >13 cirrhosis — and is now recommended in NICE NG49 for MASLD staging. HCV serology is mandated as it is now curable in >95% of cases. Haemochromatosis (transferrin saturation >45%) affects 1:200 Northern Europeans.

Refer

Referral Criteria — When to Escalate to Secondary Care

Done

Most mildly abnormal LFTs resolve in primary care; these criteria require specialist input.

999

Encephalopathy, haematemesis, haemodynamic instability, INR >2.0 with clinical deterioration → acute liver failure

Same-day

ALT >10× ULN; jaundice + fever + RUQ pain; suspected DILI with ALT >5× ULN; new coagulopathy; ascites

2WW

Painless progressive jaundice, weight loss + cholestatic LFTs (suspect pancreatic/cholangiocarcinoma). AFP raised. NICE NG12.

Urgent 2/52

ALT >3× ULN persisting >6 weeks; positive autoimmune screen; positive viral hepatitis serology; haemochromatosis confirmed; Wilson's suspected (<40y)

Routine

MASLD with FibroScan kPa >8 (significant fibrosis), PBC (AMA positive), PSC (ANCA positive + cholestatic), unexplained persistent LFT derangement >6 months

Primary care manage

Mild isolated GGT in alcohol drinker — lifestyle advice, repeat 4-6/52. Mild MASLD (FibroScan <8kPa, no features of advanced disease). Gilbert's syndrome (harmless, reassure)

BSG/BASL guidelines emphasise that ALT >10× ULN represents acute hepatitis requiring same-day assessment — acute viral hepatitis, autoimmune hepatitis, and DILI can all cause this. Autoimmune hepatitis is treatable (prednisolone + azathioprine) but if missed leads to cirrhosis. Pancreatic cancer has a 5-year survival of <5%, making early 2WW referral critical. MASLD without advanced fibrosis is largely managed in primary care with lifestyle modification.

Treat

Treatment — Cause-Specific Management Pathway

Done

Treatment depends on the underlying cause. Most causes managed in primary care have lifestyle as the cornerstone.

MASLD (most common)

Lifestyle first First-line

10% weight loss normalises LFTs in 80%. No specific drug licensed in UK. Refer T2DM patients — semaglutide/pioglitazone have evidence for MASH.

Alcoholic Liver Disease

Abstinence + support Core

Refer to alcohol services. Acamprosate 666mg TDS or naltrexone 50mg OD (if abstinent). Thiamine 200-300mg/day if nutritionally deficient.

Hepatitis C

DAA therapy Curative

Refer hepatology — direct-acting antivirals (sofosbuvir/velpatasvir 12/52) achieve >95% SVR. Do not initiate in primary care.

Hepatitis B

Tenofovir / Entecavir

Hepatology-led. HBsAg carriers need HBV DNA quantification, LFT monitoring, HCC surveillance if cirrhotic.

DILI (Drug-Induced)

Stop causative drug Urgent

Check Roussel Uclaf Causality Assessment (RUCAM). Most recover within 8-12 weeks. Corticosteroids for severe DILI with autoimmune features.

PBC (AMA positive)

Ursodeoxycholic acid

UDCA 13-15 mg/kg/day. Hepatology-prescribed. Reduces progression to cirrhosis. Add obeticholic acid if incomplete response.

Statin LFTsALT <3× ULN → continue statin (statins are hepatoprotective in MASLD). ALT >3× ULN → withhold, recheck in 4-6 weeks; rechallenge or switch statin

HaemochromatosisVenesection (hepatology-led) — 450-500ml weekly until ferritin <50 µg/L. Maintain with 4-6 weekly venesection. Advise reduce red meat intake, avoid alcohol, avoid iron supplements

Gilbert's syndromeNo treatment required. Explain benign nature. Bilirubin rises with fasting, illness, or exercise. Not associated with liver disease. Reassure and discharge.

MASLD affects 25% of UK adults — lifestyle modification (weight loss 7-10%) reduces ALT by 40-60% and liver stiffness by 30-50% (NICE NG49). Statins are frequently (and wrongly) stopped due to abnormal LFTs — the BSG/NICE guidance confirms statins do not cause clinically significant liver disease and are safe in MASLD. HCV is now curable — every positive HCV Ab should trigger HCV RNA testing and hepatology referral. Venesection in haemochromatosis, if started before cirrhosis, achieves normal life expectancy.

Lifestyle

Non-Pharmacological — The Foundation of Liver Health

Done

Lifestyle modification is the primary treatment for MASLD and alcohol-related disease — more effective than most drug interventions.

Weight loss (MASLD) Target 7-10% body weight reduction. Reduces steatosis, inflammation, and fibrosis. Each 1% weight loss reduces liver fat by ~1%.

Alcohol reduction Target <14 units/week with 2+ alcohol-free days. Complete abstinence if alcoholic liver disease. GGT normalises in 4-8 weeks of abstinence.

Exercise 150 min/week moderate aerobic activity. Resistance exercise reduces hepatic fat independently of weight loss. Benefits seen even without weight loss.

Mediterranean diet Reduce refined carbohydrates, saturated fat, processed foods. Increase vegetables, legumes, fish, olive oil. Reduces liver fat by 30-40%.

Stop hepatotoxic drugs Review all OTC supplements (herbal teas, bodybuilding supplements, kava). Check for unnecessary medications. RCGP medication review tool.

Vaccinations HAV and HBV vaccination in patients with chronic liver disease or at risk (PWID, MSM, travel). Influenza annually. Pneumococcal (PPV23) in cirrhosis.

Coffee (evidence-based!) 2-3 cups/day of caffeinated coffee is independently associated with 40% reduced risk of liver fibrosis and HCC. Advise patients this is beneficial.

Avoid NSAIDs NSAIDs + decompensated liver disease = acute kidney injury risk. Paracetamol is safer but limit to 2g/day in severe liver disease.

The LEAN trial (2016) showed 52% reduction in MASH histology with lifestyle intervention vs 0% in controls. Mediterranean diet alone reduces hepatic steatosis by 38% (PREDIMED data). Exercise reduces liver fat by 3-4% (absolute) even without caloric restriction. Coffee's hepatoprotection is now well-established — meta-analysis of 16 studies shows OR 0.40 for fibrosis with 2+ cups/day. This is one of the few genuinely evidence-based dietary recommendations in hepatology.

Safety

Follow-Up & Monitoring — Structured Review Plan

Done

Monitoring intervals depend on severity and cause. Document a clear follow-up plan.

4-6 weeks

Repeat LFTs if initially <2× ULN (mildly abnormal). Check response to lifestyle changes or drug cessation. If normalised → discharge with lifestyle advice

3 months

MASLD on lifestyle programme — repeat LFTs, weight, BMI, waist circumference. FibroScan if not yet done and LFTs persistently abnormal

6 months

Alcohol-related — LFTs, FBC, GGT trend. Assess engagement with alcohol services. AUDIT re-score.

Annual (MASLD)

LFTs, HbA1c, lipids, BP, BMI. Repeat FibroScan every 2-3 years if stable. If FibroScan worsening → re-refer hepatology

HCC surveillance

Liver ultrasound + AFP every 6 months if established cirrhosis (any cause). Do NOT do if no cirrhosis — cost-ineffective.

Safety-net 999

Haematemesis, melaena, confusion/encephalopathy, rapid deterioration with jaundice → call 999 immediately

Safety-net same-day

New jaundice, worsening RUQ pain, new ascites, significant bruising, any new neurological symptoms → same-day GP/ED

Discharge criteria

LFTs normal on 2 consecutive checks with identified and managed cause → discharge to primary care annual review if MASLD, or discharge if transient cause resolved

NICE NG49 recommends FibroScan every 2-3 years for MASLD in primary care. HCC surveillance (USS + AFP 6-monthly) reduces HCC mortality by 37% in cirrhotic patients (RCT evidence) — but is not cost-effective in non-cirrhotic patients. GGT has a half-life of ~26 days — normalisation with abstinence is useful to confirm alcohol as cause. LFTs that remain elevated after 6 months of lifestyle modification and alcohol reduction warrant re-investigation and hepatology input — a cause has likely been missed.