ABSTRACT
The purpose of this study was to determine the age-specific reference ranges for some important male sex steroid hormones, prostate-specific antigen [PSA], insulin-like growth factor-1 [IGF-1], and IGF binding protein-3 [IGFBP-3], for the Kuwaiti population. Blood samples were taken from 398 consenting, fasting, healthy Kuwaiti males aged 15-80 years between 8.00 a.m. and 12.00 noon. The serum concentrations of total testosterone [TT], dehydro-epiandrosterone sulfate [DHEAS], androstenedione [ADT], sex hormone binding globulin, luteinizing hormone [LH], follicle-stimulating hormone [FSH], prolactin, PSA, IGF-1 and IGFBP-3 were determined. A distribution curve was plotted and age-specific reference levels were determined for each analyte. The reference interval for parameters with a normal distribution [Gaussian] was mean +/- 2 SD, while for the non-normal distribution [non-Gaussian], it was 2.5-97.5 percentile. The reference intervals for the analytes obtained from this study were compared with those suggested by the kit manufacturers and currently used by the Ministry of Health, Kuwait Laboratories [MOHKL]. Serum IGFBP-3 and ADT had normal distribution while other analytes had non-normal distribution. The reference intervals from this study, manufacturers kit and MOHKL were as follows: TT 3-31, 9-60, 8-35 nmol/l; DHEAS 0.9-11, 1.0-7.3, 2.2- 15.2 micro mol/l; ADT 0.5-4.3, 0.8-2.8, 2.0-9.2 nmol/l; LH 1-11, 0.8-7.6, 0.4-5.7 mIU/l; FSH 0.5-11, 0.7-11.1, 1.1-13.5 mIU/l; prolactin 42-397, 53-360, 80-230 nmol/l; IGF-1 41-542, 78-956, 71-261 ng/ml; IGFBP-3 88- 2,090, 900-4,000, 900-4,000 ng/ml, and PSA 0-3.1, 0-4, 0-4 ng/ml, respectively. These data indicate that for Kuwaitis lower reference ranges must be used for serum TT, DHEAS, ADT, IGFBP-3 and PSA. There is no need to change the currently used reference interval for FSH whereas higher values must be used for LH, prolactin, and IGF-1