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[Biochemistry](https://durgical.com/en/biochemistry/) · Topic

# Liver function tests: reading the pattern

The liver panel mixes markers of cell injury, cholestasis and true function; the pattern points to the cause.

Updated 2026-11-01

## Key facts

- Hepatocellular injury: high ALT and AST, out of proportion to alkaline phosphatase.
- Cholestasis: high alkaline phosphatase and GGT, with or without high direct bilirubin.
- True synthetic function: albumin (half-life about 3 weeks) and prothrombin time/INR (factors with half-lives of hours).
- High indirect bilirubin with normal enzymes: haemolysis or Gilbert syndrome; high direct bilirubin: cholestasis or failed excretion.
- R factor = (ALT/ULN) ÷ (ALP/ULN): > 5 hepatocellular,
- 'Liver function tests' is a loose name: aminotransferases and alkaline phosphatase measure injury, not function.
- Aminotransferases leak from hepatocytes when their membrane breaks: viral, toxic (paracetamol), ischaemic or autoimmune hepatitis, fatty liver.
- Alkaline phosphatase and GGT are made in greater amounts by the bile canaliculi when there is obstruction or intrahepatic cholestasis.
- Bilirubin comes from haem: the indirect (unconjugated) form needs hepatic UGT1A1; the direct (conjugated) form leaves into bile through the MRP2 transporter.
- Albumin falls slowly in chronic disease; INR lengthens within hours in acute failure and is the best immediate prognostic marker.
- The Child–Pugh and MELD scores use bilirubin, albumin, INR, creatinine and sodium to grade cirrhosis.

**Also called**
LFTs, Liver panel, Hepatic panel

## Clinical notes

- Aminotransferases in the thousands: acute viral hepatitis, paracetamol or ischaemic hepatitis ('shock liver').
- An INR that does not correct with vitamin K means failed synthesis; if it corrects, it suggests cholestasis or malabsorption.
- Normal aminotransferases do not exclude advanced cirrhosis, because little tissue is left to injure.

## Pathways

- [Heme breakdown and bilirubin](https://durgical.com/en/biochemistry/pathways/heme-breakdown-and-bilirubin/)

## Related conditions

- [Viral hepatitis](https://durgical.com/en/conditions/viral-hepatitis/)
- [Cirrhosis](https://durgical.com/en/conditions/cirrhosis/)
- [Choledocholithiasis](https://durgical.com/en/conditions/choledocholithiasis/)
- [Gilbert syndrome](https://durgical.com/en/conditions/gilbert-syndrome/)
- [Hepatocellular carcinoma](https://durgical.com/en/conditions/hepatocellular-carcinoma/)

## Related

- [Aminotransferases (ALT and AST) as lab tests](https://durgical.com/en/biochemistry/topics/aminotransferases-as-lab-tests/)
- [Alkaline phosphatase (ALP) as a lab test](https://durgical.com/en/biochemistry/topics/alkaline-phosphatase-as-a-lab-test/)
- [Gamma-glutamyl transferase (GGT) as a lab test](https://durgical.com/en/biochemistry/topics/gamma-glutamyl-transferase-as-a-lab-test/)
- [Serum albumin as a lab test](https://durgical.com/en/biochemistry/topics/serum-albumin-as-a-lab-test/)
- [Bilirubin](https://durgical.com/en/biochemistry/molecules/bilirubin/)

## Test yourself

Think of the answer, then tap the question to see it.

## Which marker best reflects acute hepatic synthetic function?

Prothrombin time/INR, because clotting factors have half-lives of hours, against weeks for albumin.

## Which pattern suggests biliary obstruction?

Alkaline phosphatase and GGT raised more than the aminotransferases, with high direct bilirubin.

## Why can albumin be normal in severe acute hepatitis?

Its half-life is about three weeks: it takes time to fall even when synthesis is already failing.

## What does isolated indirect hyperbilirubinaemia with normal enzymes suggest in a young adult?

Gilbert syndrome (low UGT1A1 activity) or haemolysis.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Liver Function Tests: MedlinePlus Medical Test](https://medlineplus.gov/lab-tests/liver-function-tests/) (MedlinePlus, US National Library of Medicine, 2026); [Bilirubin Blood Test: MedlinePlus Medical Test](https://medlineplus.gov/lab-tests/bilirubin-blood-test/) (MedlinePlus, US National Library of Medicine, 2026); [Total Protein and Albumin/Globulin (A/G) Ratio: MedlinePlus Medical Test](https://medlineplus.gov/lab-tests/total-protein-and-albumin-globulin-a-g-ratio/) (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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