Liver enzyme tests and others

ALT and AST

Liver enzymes are proteins with specific functions (and difficult long names).

If the liver becomes damaged, some of these enzymes leave the liver and enter the blood.

Many things can cause liver enzyme levels to increase. These include:

• Prescription and over-the-counter medicines.
• Herbs, vitamins and supplements.
• Toxic fumes.
• High alcohol intake or coming off drugs and/or alcohol.
• New or existing hepatitis infection.

HIV drugs can cause liver enzymes to increase, though usually not to dangerous levels. In some cases, these drugs need to be stopped or switched.

People taking HIV drugs (or other drugs processed by the liver) need to have liver enzymes routinely measured with other blood tests. This is especially important with HCV coinfection.

Raised liver enzymes do not always mean there is liver damage. But persistently high levels can be a sign of ongoing damage that needs to be treated.

Measuring liver damage

Before starting HCV treatment it is important to check for liver damage.

People with cirrhosis (advanced liver scarring) may need to be treated by a liver specialist, and may need to avoid certain DAAs.

Last updated: 1 November 2024.