Reasoning GP · Algorithm · 1-page summary
Abnormal liver blood tests in adults
For: adults with abnormal LFTs, incidental or symptomatic. Not for: children or adolescents (local pathways; adult thresholds do not apply). Pregnancy, post-partum → block 2.
Core rule: name the pattern, then investigate the cause — never re-test and wait. The size of the rise does not predict severity and normal LFTs do not exclude cirrhosis: albumin, INR, platelets, bilirubin and fibrosis staging do.
0Stop — emergency admission now — 999 or immediate acute or hepatology discussion
- Jaundice with confusion, drowsiness, raised INR, hypoglycaemia or ascites → 999. Acute liver failure = acute injury, no known cirrhosis, INR typically ≥1.5 and new encephalopathy; a raised INR alone is not.
- Any paracetamol overdose, staggered or therapeutic-excess, or suspected self-harm, whatever the bloods → Immediate hospital; do not wait for a level.
- Haematemesis or melaena · shock or severe sepsis · marked or rapidly rising transaminases with systemic illness → 999
- Hand over albumin, INR, platelets, U&E, glucose, paracetamol and alcohol history, all drugs and supplements.
1Name the pattern
| ALT-dominant | MASLD, alcohol, drugs, hepatitis B/C, autoimmune, iron, coeliac, thyroid, Wilson's |
| ALP + GGT | Gallstones, obstruction, drugs, PBC, PSC, cancer → ultrasound |
| ALP, GGT normal | Bone, vitamin D deficiency, pregnancy → bone profile, vitamin D |
| Isolated GGT | Alcohol, metabolic, drugs; persistent unexplained is not dismissed |
| Bilirubin only | Unconjugated: Gilbert's once haemolysis excluded; conjugated: never |
2Screen — one row is enough
- Jaundice + fever + RUQ pain (cholangitis) → Same-day hospital; 999 if hypotensive, confused or septic.
- Known liver disease, new ascites, confusion or bleeding → Admit now. Painful or febrile ascites = SBP until tapped.
- New painless jaundice, dilated duct, pale stools, dark urine; or rising transaminases → Same / next day, urgent ultrasound, INR, full screen.
- Harmful or dependent drinking → Admit if jaundiced, encephalopathic or withdrawing; else Same-day + alcohol service.
- Pregnant with itch, raised BP, epigastric pain or vomiting → Same-day maternity; 999 if hypertensive, unwell or vomiting.
- NG12: jaundice ≥40 → Suspected cancer: pancreatic, not 999 · liver or gallbladder mass → urgent ultrasound · ≥60, weight loss + new diabetes, back pain, nausea or bowel change → urgent CT.
3Assess — one go, not in stages
☐ Alcohol units (AUDIT-C); drugs and supplements in 6 months; metabolic and blood-borne virus risk; previous results ☐ Liver signs, ascites, mass
☐ Ultrasound, HBsAg, HCV antibody, ferritin + transferrin saturation, ANA, AMA, SMA, immunoglobulins, caeruloplasmin if under 40, coeliac, TFTs, HbA1c, lipids, FBC, U&E, INR, albumin
☐ Then fibrosis, local pathway: ELF ≥10.51 → hepatology, or FIB-4 <1.3 low risk (<65), ≥1.3 → ELF or elastography. Low FIB-4 does not exclude.
4Classify — once urgency is settled
- Fatty liver — metabolic risk, bright liver, negative screen → stage fibrosis.
- Alcohol — AST:ALT >2 (supportive only), GGT, MCV, low platelets. Men >50, women >35 units/week for months → offer fibrosis assessment.
- Drug-induced — any drug or product in 6 months (co-amoxiclav, flucloxacillin, herbal) → stop if non-essential and safe, recheck 4–6 weeks. Severe → Same-day hospital
- Viral, autoimmune, inherited — positive virology, IgG + ANA/SMA, transferrin saturation >45%, low caeruloplasmin → block 6.
- Gilbert's — unconjugated, normal enzymes and FBC, no haemolysis, >1 result → benign.
- Uncertain — abnormal beyond 3–6 months, negative screen, indeterminate FIB-4 → say so, refer.
5Treat today
- Fatty liver: treat as cardiometabolic disease — 7–10% weight loss, diet, 150 min/week activity; optimise diabetes, BP, lipids.
- Statins: do not withhold for stable transaminases <3× ULN. Persistent unexplained >3× → investigate, usually withhold pending review.
- Alcohol dependence: no abrupt cessation without support (seizures, delirium tremens); thiamine where indicated; alcohol service now.
- Ascites, decompensation: avoid NSAIDs; reduced paracetamol maximum, no duplicates. Doses: NICE/SPC, BNF, local formulary.
6Refer
- ≤2 weeks HBsAg positive · HCV RNA positive · suspected autoimmune hepatitis (before steroids) · any cirrhosis · iron overload · Wilson's (<40).
- Routine ELF ≥10.51 or high-risk FIB-4 · AMA-positive cholestasis · cholestasis with IBD (MRCP) · unexplained beyond 3–6 months, screen in the letter.
- Cirrhosis: 6-monthly HCC ultrasound ± AFP, variceal screening (NG50).
7Never reassure by
- A "mildly" raised ALT, repeated for months.
- Normal LFTs — cirrhosis, hepatitis B and C still possible.
- "Fatty liver" without a fibrosis score; "alcohol" without units.
- A low FIB-4 or the AST:ALT ratio alone.
- "Gilbert's" without excluding haemolysis.
- A normal ultrasound with persisting jaundice.
8Safety-net — say it, then document it
999 “Call 999 for confusion or marked drowsiness, vomiting blood or black stools.” Same day “Contact us or 111 today if your skin or eyes turn yellow, you bruise or bleed easily, your abdomen swells, or you have fever with jaundice or upper abdominal pain.”
Remote or inbox (never leave a jaundiced or coagulopathic result overnight): convert to face-to-face or emergency assessment for jaundice, confusion or drowsiness, a paracetamol history, pregnancy, known cirrhosis, or marked or rapidly rising transaminases.
✓Safe to manage in primary care only if — all five, documented
No block 0–2 row; no jaundice, encephalopathy or ascites
Albumin, INR, platelets normal; pattern named
Screen negative bar a modifiable cause; fibrosis low risk
Alcohol quantified, drugs reviewed, NG12 considered
Recheck, reviewer and thresholds written; safety-net given
Summary of the full Reasoning GP abnormal liver blood tests algorithm, which holds the history, examination, targeted tests, treatment and follow-up. Sources: BSG 2017; NICE NG49, NG50, CG100, CG115, NG12 (updated April 2026), NG253, CG165, NG238. Clinical reference — follow local pathways and check doses: NICE/SPC, BNF.