Health-based reference intervals for ALAT, ASAT and GT in serum, measured according to the recommendations of the European Committee for Clinical Laboratory Standards (ECCLS).

The reference intervals for the activities of L-alanine aminotransferase (EC 2.6.1.2, ALAT), L-aspartate aminotransferase (EC 2.6.1.1, ASAT) and gamma-glutamyltransferase (EC 2.3.2.2, GT) in serum were determined according to the recommendations of the European Committee for Clinical Laboratory Standards (ECCLS). Serum specimens from 954 subjects were analysed for ALAT and ASAT and from 794 subjects for GT. The subjects, aged 27-67 years, were participants in general health surveys. The reference population was formed by excluding subjects with any disease, or on any medication, affecting the liver, and also those consuming excessive amounts of alcohol. The 95% inner reference intervals for ALAT and ASAT were 9-50 (n = 189) and 15-36 U l-1 (n = 192) in men and 8-38 (n = 270) and 13-33 U l-1 (n = 270) in women. For GT the reference interval was 11-58 in men (n = 165) and 8-42 U l-1 in women (n = 220). Serum GT levels correlated clearly with alcohol consumption. Serum ALAT and ASAT were only slightly associated with alcohol consumption at levels less than 280 g per week in men and 190 g per week in women. There were modest positive associations between the three enzyme levels and body mass index. None of the enzymes correlated significantly with age.