Liver Function Tests: What ALT and AST Actually Mean
If you’ve ever seen “ALT” and “AST” on a lab report and wondered what they actually measure, you’re not alone — these are two of the most common but least-explained numbers in a general checkup.
ALT and AST are enzymes that live mostly inside liver cells. When the liver is under stress or damaged, these enzymes leak into the bloodstream in higher amounts. Our Liver Function Panel measures both, along with bilirubin, albumin, and total protein, for a fuller picture of how your liver is doing.
Why people order this test
- Monitoring the effects of alcohol use over time
- Checking a medication that’s known to affect the liver
- Following up on an earlier abnormal result
- General health screening
What to expect
No fasting is typically required, though your instructions will confirm this.
Ready to order? The Liver Function Panel is $34 at SelectATest, with results in your own secure online portal.
This post is for general information and does not replace advice from your own doctor. Tests are ordered by an independent licensed physician, and results are not a diagnosis. If you are having a medical emergency, call 911.