Alanine aminotransferase

Alanine aminotransferase
S -ALAT KL 1026

(In English S -ALT)

Alanine aminotransferase, also known as ALT, is an enzyme that plays a significant role in amino acid metabolism. It facilitates the transfer of an amino group from alanine to alpha-ketoglutarate, leading to the formation of pyruvate and glutamate. While the primary concentration of the ALT enzyme is in the liver, smaller amounts can also be found in the muscles, lungs, kidneys, and heart.


Diagnostics and monitoring of liver diseases.


1 mL of non-hemolysed serum (minimum 0.5 mL)

Storage and delivery

The sample can be stored for 7 days in a refrigerator or freezer (-20 °C). Ship the sample as room-temperature, if it arrives within 24 hours. Can be stored refrigerated over the weekend.

Extended freezing can lead to a decrease in ALT activity.


Photometric, in accordance with IFCC recommendation. Accredited method.

Turnaround time

1-2 weekdays

Reference ranges

children, 0 – 16 yrsbelow 40U/I
men, from 17 yrs 10 – 70 U/I
women, from 17 yrs 10 – 45 U/I
The reference values for adults are established using the data from the reference value material published by Huslab (2014).

Interpretation of results

Elevated ALT values typically indicate inflammation or damage to liver cells. In cases of acute hepatitis, whether caused by a virus or medication, ALT levels can increase significantly compared to the reference values. These elevated values may even be observed during the subclinical phase of the disease, prior to the appearance of jaundice. As chronic hepatitis or liver cirrhosis progresses, the initially elevated ALT value tends to decrease, reflecting a reduction in the number of liver parenchymal cells.

Furthermore, conditions such as bile duct obstructions and intrahepatic biliary stasis can lead to an increase in ALT levels. Obesity and fatty liver, as well as long-term heavy alcohol consumption, may also contribute to elevated ALT values. However, consuming large amounts of alcohol for a short period typically does not cause an increase in ALT levels. Additionally, certain medications, including paracetamol, statins, oxycodone, and other drugs, can result in higher ALT values.

Apart from liver damage, increased ALT values can also be linked to conditions such as pulmonary infarction, kidney failure, sepsis, and muscular dystrophy.


Last update 8.8.2023