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REASONING GP · Clinical algorithm · Quick reference
Abnormal liver blood tests in adults — triage and diagnostic approachDecide the pattern, then investigate the cause — never re-test and wait. A mildly raised ALT is the commonest finding and fatty liver the commonest cause; the risk is fibrosis, which the enzymes do not show.
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| Trigger / red flag | Leading concern · destination | Do now · do not delay |
|---|---|---|
| Jaundice with encephalopathy, coagulopathy, hypoglycaemia or ascites; or ALT above about 1000 U/L; or any paracetamol overdose or staggered ingestion, whatever the bloods show. | Acute liver failure · paracetamol toxicity Emergency admission now |
Check INR, albumin, glucose and platelets — these, not the ALT, define severity, and an INR above 1.5 with jaundice is acute liver failure. Ask directly about paracetamol, including staggered and therapeutic-excess ingestion: treatment is time-critical and cannot wait for a level in a staggered overdose. Send the drug list, alcohol history and any herbal or gym supplements. |
| Jaundice with fever and right upper quadrant pain (Charcot's triad), rigors or hypotension; or known chronic liver disease with new decompensation — new ascites, encephalopathy, jaundice, haematemesis, melaena or spontaneous bruising. | Ascending cholangitis · decompensated cirrhosis · variceal bleed · spontaneous bacterial peritonitis Emergency admission now |
Cholangitis needs emergency biliary decompression, not an oral antibiotic and a scan request — say "jaundice, fever, RUQ pain — query cholangitis" so the ERCP pathway starts from the call, with a sepsis assessment (NG51). In decompensation, any new ascites with pain or fever is SBP until tapped; stop nephrotoxics, NSAIDs and sedatives and review diuretics, rather than increasing spironolactone at a distance in a confused or bleeding patient. |
| New jaundice without pain, fever or encephalopathy, or a cholestatic pattern with a dilated duct; pale stools, dark urine, pruritus. Or ALT above 3–5 times the upper limit, a rapidly rising ALT, or abnormal LFTs with systemic upset, weight loss or an autoimmune history. | Biliary obstruction · pancreatic or biliary malignancy · acute, autoimmune or drug-induced hepatitis Same-day or next-day assessment; urgent imaging and advice if unwell or coagulopathic |
New jaundice is never a routine referral: arrange an urgent liver ultrasound and same-day bloods with a coagulation screen, and note that painless jaundice raises malignancy — the NG12 row gives the age-specific route. Send the full non-invasive liver screen at once, not in stages: hepatitis B surface antigen and C antibody, ferritin and transferrin saturation, autoantibodies (ANA, AMA, SMA) with immunoglobulins, coeliac serology, TFTs, HbA1c, lipids, FBC, INR and albumin. Stop the suspected drug — ask about anything new in 3 months (co-amoxiclav, flucloxacillin) and gym or herbal supplements. Autoimmune hepatitis needs hepatology before steroids. |
| Alcohol dependence or harmful drinking with abnormal LFTs — especially an AST:ALT above 2, raised GGT, macrocytosis, thrombocytopenia or withdrawal symptoms; or a high bilirubin after recent heavy drinking. | Alcohol-related hepatitis · cirrhosis · withdrawal and Wernicke's risk 999 or admission if jaundiced, encephalopathic or withdrawing Same-day assessment; urgent alcohol service referral |
Severe alcohol-related hepatitis has a high mortality and needs specialist care. Never advise abrupt cessation in dependence without support — unplanned withdrawal risks seizures and delirium tremens (CG100, CG115). Prescribe oral thiamine; admit for parenteral thiamine if Wernicke's is suspected. Refer to the alcohol service at this visit. |
| Abnormal LFTs in pregnancy: raised transaminases or bilirubin with itching (especially palms and soles), hypertension, headache, epigastric pain, vomiting or malaise — particularly after 20 weeks. | Pre-eclampsia and HELLP · obstetric cholestasis · acute fatty liver of pregnancy 999 if hypertensive, unwell or vomiting Same-day maternity assessment |
Abnormal LFTs in pregnancy are an obstetric problem: check the BP and send urine protein immediately, and speak directly to the maternity unit. Itching of the palms and soles with raised bile acids is obstetric cholestasis. Acute fatty liver of pregnancy presents after 20 weeks with vomiting and malaise, and is life-threatening. |
| Cancer features with abnormal LFTs: jaundice at 40 or over · an upper abdominal mass consistent with an enlarged liver or gallbladder · 60 or over with weight loss plus new diabetes, back pain, nausea, vomiting or bowel change · dysphagia at any age · 55 or over with weight loss and upper abdominal pain. | Pancreatic · hepatobiliary · upper GI cancer Urgent suspected-cancer referral within 2 weeks for jaundice at 40+ or a liver/gallbladder mass · urgent direct-access CT (or ultrasound if CT unavailable) at 60+ · urgent direct-access OGD for dysphagia or 55+ with weight loss · NICE NG12 |
Match the route to the criterion (NG12) and state the LFT pattern in the request. Painless jaundice at 40 or over is an urgent suspected-cancer referral, not a routine hepatology letter. Cirrhosis or chronic hepatitis B needs 6-monthly HCC ultrasound surveillance (NG50). A normal ultrasound with persisting jaundice does not close the question. |
REASONING GP · Abnormal liver blood tests in adults — triage and diagnostic approach |
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| Fatty liver and alcohol ALT-dominant | Fatty liver (MAFLD/NAFLD) — the commonest cause of a mildly raised ALT: obesity, type 2 diabetes, hypertension, a bright liver on ultrasound, negative screen. The ALT does not indicate severity and may be normal in cirrhosis, so stage the fibrosis; an AST:ALT above 1 suggests it is advancing. Alcohol — AST:ALT above 2 with a raised GGT, macrocytosis and thrombocytopenia; quantify with AUDIT-C. Abstinence reverses much, but abrupt cessation in dependence is dangerous without support (CG100, CG115). |
| Drug-induced liver injury either pattern | Any drug started within 3 months: antibiotics (co-amoxiclav, flucloxacillin, macrolides), methotrexate, azathioprine, statins, NSAIDs, amiodarone, herbal and bodybuilding supplements. Stop the suspect, recheck at 4–6 weeks, record it as a suspected reaction. A statin need not stop for a mild rise — but does above 3 times normal. |
| Viral, autoimmune, inherited and cholestatic — the specialist limb | Hepatitis B or C — refer all positives; both treatable, hepatitis C curable. Autoimmune hepatitis — raised IgG with positive ANA or SMA; hepatology before steroids. Haemochromatosis — transferrin saturation above 45% with a raised ferritin, needing HFE genotyping. Wilson's — under 40, low caeruloplasmin. Cholestatic — confirm hepatic origin with the GGT first, then gallstones and biliary obstruction (dilated ducts), drugs, primary biliary cholangitis (AMA-positive, itch and fatigue), sclerosing cholangitis (with IBD, needing MRCP), and malignant obstruction — the NG12 route, not a routine referral. |
| Gilbert's, bone ALP, and what not to conclude | Gilbert's: isolated unconjugated hyperbilirubinaemia, normal enzymes, no haemolysis — benign, no follow-up. Isolated ALP with a normal GGT: bone or pregnancy, not liver. Do not conclude: "fatty liver" without a fibrosis score · "alcohol" without asking the units · "repeat in 3 months" as an endpoint · "normal LFTs, so no cirrhosis". |
| Send the whole screen and stage the fibrosis, then address the drug and the alcohol | Screen: do it in one go — virology, iron studies, autoantibodies with immunoglobulins, coeliac serology, TFTs, HbA1c, lipids, FBC, INR, albumin, ultrasound — and calculate FIB-4 at the same time, because staging the fibrosis changes outcomes and re-testing the ALT is not a substitute. Drug: stop the suspect and recheck at 4–6 weeks, recording it as a suspected adverse reaction; ask specifically about herbal, gym and weight-loss supplements, which patients do not report as medicines. Continue a statin for a mild isolated rise; stop above 3 times the upper limit. Alcohol: quantify with AUDIT-C and advise today, but in dependence do not advise abrupt cessation without support — withdrawal risks seizures and delirium tremens. Prescribe oral thiamine, refer to the alcohol service now, and admit if there is jaundice, encephalopathy or established withdrawal (CG100, CG115). |
| Fatty liver, recheck, and what not to do | Fatty liver with a low fibrosis score: treat it as cardiometabolic disease, because that is what kills these patients — 7–10% weight loss, a Mediterranean-style diet, 150 minutes of activity weekly, alcohol reduction, optimised diabetes, BP and lipids, and a statin, which is not contraindicated and is usually indicated (NG49). Recheck: LFTs with albumin, INR and platelets at 4–6 weeks after any change, then 6–12 months once stable, with the triggers written down — jaundice, confusion, drowsiness, bruising, vomiting blood or black stools, or abdominal swelling → emergency admission; ALT above 3–5 times normal, a rising bilirubin, a falling albumin or platelets → urgent specialist advice. Do not: repeat the LFTs for months instead of investigating · reassure on normal enzymes, which do not exclude cirrhosis · investigate a raised ALP without a GGT · call an isolated bilirubin Gilbert's without excluding haemolysis · refer painless jaundice at 40 or over routinely (an NG12 route) · or advise abrupt alcohol cessation in dependence. |