Description
ALT is an enzyme that catalyses the transfer of α-amino groups from alanine to the α-keto group of ketoglutaric acid to generate pyruvic acid which is an important contributor to the citric acid cycle. ALT is highly concentrated in the liver, however, low concentrations are found in skeletal muscles and the kidneys. In the liver, ALT is localised solely in the cellular cytoplasm. ALT is cleared by sinusoidal cells within the liver and its half-life in the circulation is about 47 hours.
Indications
The magnitude and rate of change of aminotransferase alteration may provide initial insight into a differential diagnosis; very high aminotransferase levels (> 75 times the upper reference limit) indicateischemic or toxic liver injury in more than 90% of cases of acute hepatic injury, whereas they are less commonly observed with acute viral hepatitis. Patients with a marked increase in aminotransferase levels (more than 10 times the upper normal limit) typically have acute hepatic injury. Moderate increase (between 5 - 10 times the upper normal limit)are suggestive of acute viral hepatitis. In cases of acute viral hepatitis, aminotransferase levels usually peak before jaundice appears and have a more gradual decrease thereafter, whereas in ischemic injury, aminotransferase levels tend to decrease rapidly after peaking. Viral hepatitis (A, B, C, D and E) may be responsible for a marked increase in aminotransferase levels, although the increase associated with hepatitis C infection tends to be more modest than that associated with hepatitis A or B.
Sample Type, Quantity & Conditions
1 ml Serum 1 ml K2-EDTA or Li-Heparin Plasma Stability: 3 Days at 15-25 °C 7 Days at 2-8 °C > 7 Days at (-60)-(-80) °C
Special Precautions
Avoid haemolysed samples.
Normal Range
Male: Up to 41 U/L Up to 0.68 µkat/L Female: Up to 33 U/L Up to 0.55 µkat/L
