ALT Alanine Aminotransferase

What Does This Test Check?

Alanine aminotransferase (ALT) is an enzyme that sits inside liver cells. When the liver is irritated, ALT leaks into the blood, which makes it the most sensitive routine marker of liver strain.

Lola Health lists this as an add-on biomarker at £12, posted as a home sample with results in one to four working days. It cannot be bought on its own: you pick it while ordering one of Lola's main blood tests, so it suits someone who already knows which extra marker they want.

A raised level may indicate liver irritation from alcohol, medication, fatty liver or vigorous exercise the day before. Mild raises are common and often settle on a repeat. Whatever the reading, an out-of-range result needs a doctor who can see the whole picture, so go through it with your GP before acting on it.