Patient Guide

Complete Guide to Liver Function Tests (LFTs)

Name: Complete Guide to Liver Function Tests (LFTs) | HealthReview
Creator: Suman Konda
Published: 2026-07-05

A liver function test panel includes 6–8 different measurements. Each one tells a different story about your liver. This guide explains every result in plain English.

Written by Suman Konda, PharmD, Clinical Pharmacist · Editorial policy · Not medical advice

Last updated: 01 August 2026 · How we check our content

What each LFT measures

Test	Normal Range	What it reflects
ALT (Alanine aminotransferase)	7–56 U/L	Liver cell damage: most specific liver enzyme
AST (Aspartate aminotransferase)	10–40 U/L	Liver cell damage: also raised in muscle and heart disease
ALP (Alkaline phosphatase)	44–147 U/L	Liver or bile duct disease; bone disease
GGT (Gamma-GT)	Men: <71 U/L; Women: <42 U/L	Bile duct disease; alcohol use
Bilirubin (total)	0.1–1.2 mg/dL	Jaundice: from red cell breakdown or bile duct obstruction
Albumin	3.5–5.0 g/dL	Liver synthetic function: low in chronic liver disease
Total protein	6.3–8.2 g/dL	Combined albumin and globulin
INR / Prothrombin time	INR 0.8–1.2	Clotting factor production: impaired in severe liver disease

How to read your LFT pattern

Hepatocellular vs cholestatic pattern

Hepatocellular pattern (liver cell damage): ALT and AST raised much more than ALP. Causes: hepatitis (viral, alcoholic, autoimmune), fatty liver disease, paracetamol overdose. Cholestatic pattern (bile duct obstruction): ALP and GGT raised more than ALT and AST. Causes: gallstones, bile duct cancer, primary biliary cholangitis. Mixed pattern: both groups raised, seen in severe hepatitis or drug reactions.

What does a raised ALT mean?

ALT is the most liver-specific enzyme. Causes of raised ALT by level: mild (1–3x normal): fatty liver (NAFLD), alcohol, medications, thyroid disease; moderate (3–10x): hepatitis B or C, drug-induced liver injury, autoimmune hepatitis; severe (>10x): acute viral hepatitis, ischaemic hepatitis ("shock liver"), paracetamol overdose, acute biliary obstruction. Isolated mild ALT elevation (1–2x normal) is very common and often from fatty liver.

LFT checklist for patients

Questions to discuss with your doctor

Which tests are abnormal: liver enzymes or liver function?
Is the pattern hepatocellular or cholestatic?
Do I need a liver ultrasound?
Should alcohol or medication be reviewed?
Do I need tests for hepatitis B or C?
Should I lose weight to help a fatty liver?

Frequently Asked Questions

What do liver function tests actually measure?

They include enzymes (ALT, AST, ALP, GGT) that leak from damaged liver cells or bile ducts, plus bilirubin and albumin that reflect how well the liver is working: together giving a picture of liver health.

Can liver tests be abnormal without liver disease?

Yes. Vigorous exercise, some medications, alcohol, and even muscle injury can affect these results, which is why patterns and repeat testing matter more than a single value.

What does a raised ALT and AST indicate?

Raised ALT and AST usually reflect liver cell injury, from causes such as fatty liver, viral hepatitis, alcohol, or medications. The ratio between them and other tests helps narrow the cause.