[Cholinesterase (EC 3.1.1.8) with butyrylthiocholine-iodide as substrate: references depending on age and sex with special reference to hormonal effects and pregnancy].

Referance values are reported for the assay of cholinesterase (substratae: butyrylthiocholine iodide) in serum at 25 degrees C. There was no evidence of any age-dependency or sex-specific distinction in children (1 to 15 years, N = 309), nor were there any age-dependent changes observed in males (16 to 94 years, N = 718). Compared with the reference range for children, there was no detectable difference in the location and distribution of catalytic cholinesterase concentrations. In females (16 to 99 years, N = 861), an age-dependent difference in cholinesterase values became apparent: Regardless of pregnancy or use of hormonal contraceptives, the catalytic concentrations were found to be lower in younger females (16 to 39 years) than in older ones (greater than or equal to 40 years); the reference values in the older age group (40 to 99 years) did not differ from those of males and children. Therefore the following reference values are proposed (in each case 2.5 to 97.5 percentile: Children, males and females above 40 Years: 3.5 to 8.5 kU/l, Females (16-39 years, nonpregnant, not taking hormonal contraceptives): 2.8 to 7.4 kU/l, Females (18-41 years, pregnant or taking hormonal contraceptives): 2.4 to 6.0 kU/l.