How to read liver function tests
Other platforms explain it with text and video. In VMS you practice it on the patient.
Liver tests are ordered for many reasons, from jaundice to drug monitoring. Reading them as a pattern, not one number at a time, points you to the cause.
Step by step
Know what each test shows
ALT and AST rise when liver cells are injured. Alkaline phosphatase (ALP) and GGT rise when bile flow is blocked. INR and albumin show how well the liver makes proteins. [1]
Find the pattern
ALT and AST much higher than ALP is a liver cell (hepatocellular) pattern. ALP and GGT higher than ALT and AST is a blocked bile (cholestatic) pattern. [1]
Look at the size
Values in the thousands suggest acetaminophen injury, poor blood flow to the liver or acute viral hepatitis. [1]
Check the AST to ALT ratio
AST about twice ALT or more suggests alcohol-related liver disease. [1]
Check bilirubin
High direct (conjugated) bilirubin suggests liver disease or a blocked bile duct. High indirect bilirubin alone suggests hemolysis or Gilbert syndrome. [1]
Confirm the source of ALP
High ALP with normal GGT often comes from bone, not the liver. [1]
Judge true liver function
A rising INR or falling albumin means the liver is failing to make proteins. Report this urgently along with any confusion. [2]
Common errors
- Calling a raised ALT poor liver function when INR and albumin are normal.
- Missing a bone source for a high ALP.
- Ignoring a rising INR in acute liver injury.
Typical adult ranges; use your lab's ranges [1]
| Test | Typical range | Rises mainly with |
|---|---|---|
| ALT | About 7 to 56 U/L | Liver cell injury |
| AST | About 10 to 40 U/L | Liver, muscle or heart injury |
| ALP | About 44 to 147 U/L | Blocked bile flow or bone disease |
| Total bilirubin | About 0.1 to 1.2 mg/dL | Liver disease, bile blockage or hemolysis |
| Albumin | 3.5 to 5.0 g/dL | Falls with liver failure, malnutrition, illness |
Practice it in VMS
In VMS you do this on the patient, not on paper: every step goes on the checklist with a score, and in Teach mode Blocky tells you what comes next.
VMS cases that train this skill
Sources
Facts and steps follow AAMC Core Entrustable Professional Activities (Core EPAs); NCCPA PANCE Content Blueprint. VMS is not affiliated with these organizations. Updated: 2026-10-11.