Alanine aminotransferase

Alanine aminotransferase (ALT)

Enzyme that catalyzes amino group transfer between alanine and α-ketoglutarate

SGPT

Old name of ALT (Serum Glutamic Pyruvic Transaminase)

EC number of ALT

2.6.1.2

Function of ALT

Catalyzes conversion of alanine and α-ketoglutarate to pyruvate and glutamate

Coenzyme of ALT

Pyridoxal phosphate (Vitamin B6)

Half-life of ALT

24 hours

Highest concentration of ALT

Liver

Low concentration sites of ALT

Pancreas, heart, skeletal muscle, RBCs, stomach, gut

ALT increase conditions

Hepatocellular disorders, viral hepatitis, obstructive jaundice, cirrhosis, AMI, infections, muscular dystrophy

De Ritis ratio

Ratio of AST to ALT used to determine liver disease origin

De Ritis ratio 1–2

Non-viral origin (cirrhosis)

De Ritis ratio >2

Alcoholic hepatitis or hepatocellular carcinoma

De Ritis ratio <1

Viral hepatitis

ALT laboratory methods

Coupled enzyme reaction, Reitman-Frankel, Diazonium coupling, Babson

Wavelength for ALT assay

340 nm

Reaction temperature

37°C

Number of readings

4 readings (initial + 1, 2, 3 minutes)

Interference - bilirubin

30 mg/dL causes false increase in ALT

Interference - triglycerides

2000 mg/dL causes false decrease in ALT

Interference - hemoglobin

2.5 g/dL causes false increase in ALT

Normal ALT value

Up to 41 IU/L

Normal ALT (male)

Up to 45 IU/L

Normal ALT (female)

Up to 35 IU/L

Conversion factor

U/L × 0.017 = ukat/