Testosterone elisa kit

Serum levels of testosterone and estrogen were measured according to the manufacturer. Testosterone levels were measured using the Testosterone ELISA kit (#29K116 42K034DRG Instruments GmbH, Germany). The assay detection limit for testosterone was 0.083 ng/mL. The intra-assay coefficient of variation for each assay was between 3.28% and 4.16%. The inter-assay coefficient of variation for each assay was between 4.73% and 9.94%. Estrogen levels were measured using the Estrogen ELISA kit (#42K026-3DRG Instruments GmbH,Germany) (25 (link), 26 (link)). The assay detection limit for estradiol was 10.60 pg/mL. The intra-assay coefficient of variation for each assay was between 8.70% and 9.23%. The inter-assay coefficient of variation for each assay was between 6.87% and 14.91%.

Venous blood samples were drawn from all 60 children into sterile polypropylene tubes containing K2 EDTA (Sarstedt, Nümbrecht, Germany) using standardized procedures the same month of the year from 8:00 to 10:00 a.m. in respect of the circadian [48 (link),49 (link)] and infradian [50 (link),51 (link)] rhythm of testosterone fluctuations from all children at the Pediatric Department of Children Faculty Hospital CU in Bratislava. Whole blood samples were centrifuged for 5 min at 2000 g immediately after collection. Plasma aliquots were stored at −20°C for not longer than one month. On the day of testing, frozen samples were brought to room temperature and pipetted on to a testing plate. The ELISA assay using a commercial Testosterone ELISA kit was used according to manufacturer's instructions (DRG Instruments GmbH, Marburg, Germany). The intra-assay coefficient of variation was lower than 5% and the inter-assay coefficient of variation was 10%in every measurement. Unfortunately, plasmatic testosterone levels were measured only in 40 boys due to lack of blood sample volumes.