The Liver

What Your Liver Is Trying to Tell You: A Plain-English Guide to Liver Function Tests

Your doctor hands you a lab report. It’s a wall of abbreviations — ALT, AST, GGT, ALP — followed by numbers that mean absolutely nothing to you. You Google one of them, land on a medical journal written for hepatologists, and close the tab immediately. You’re no better off than when you started.

That’s the problem this essay is trying to solve.

The liver is one of the most underappreciated organs in the body. It sits quietly in your upper right abdomen, doing somewhere north of 500 different jobs — filtering toxins, producing bile, storing energy, synthesizing proteins, regulating metabolism, and managing your blood’s clotting ability.

It is, without exaggeration, the body’s most versatile organ. And when something starts going wrong with it, even when you still feel fine, a panel of blood tests called liver function tests (LFTs) is often the first place trouble shows up.

Here’s what those tests actually mean, in language that doesn’t require a medical degree.