A competitive immunochromatographic strip assay for 17-α-hydroxy progesterone using colloidal gold nanoparticles

► Reported an ICS assay for 17-α-hydroxy progesterone in serum for the first time. ► Test strip is semi-quantitative and can be used for screening of CAH patients. ► Lower detection limit of ICS assay is 2.5 μg/l by visual observation. ► Assay gives result in 15 min. ► IC test strips were specific and stable at 4 °C for two months.