ALT (Alanine aminotransferase)

Clinical Biochemistry

Background Information

Alanine aminotransferase (ALT) is primarily an enzyme marker of hepatocellular damage, but may also be increased in muscle damage.

Patient Preparation

No specific patient preparation is required.

Sample Requirements

For adults, 5 ml of blood taken into a 5mL gold top gel tube (or rust top for the Acute Unit)

For children, blood taken into a 3.5mL rust top tube

For neonates, blood taken into a 0.8mL minicollect lithium heparin tube.

Storage/Transport

Send at ambient temperature to the laboratory. If unavoidable, samples can be stored refrigerated overnight.

Required Information

Relevant clinical details including known or possible diagnoses; medication or recent exposure to possible hepatotoxic agents; recent foreign travel or contact with viral hepatitis.

Turnaround Times

The assays are run throughout the day and night. The in-lab turnaround time is normally less than 24 hours. The test can be ordered as an urgent request.

Reference Ranges

Male: Less than 50 U/L

Female: Less than 35 U/L

Significantly raised ALT (>3 x ULN) or persistently mildly raised ALT (for 3 - 6 months) should be further investigated, for more information on this visit G-Care.

Further Information

To learn more about ALT, visit Lab Tests Online

Page last updated: 09/04/2026 | Page last reviewed: 09/04/2026