Urinary steroid profiles: comparison of spot and 24-hour collections.

Urinary steroid profiling is commonly used in clinical routine for the diagnosis of steroid-related diseases through the analysis of absolute steroid excretion values as well as apparent enzyme activities based on catalysed product-to-precursor ratios. To compensate for diurnal fluctuations in steroid concentrations, 24 hour collections are preferred yet impractical and sometimes not feasible. We therefore measured 40 steroid metabolites by GC-MS in 24 hour and spot urine samples of healthy volunteers and systematically evaluated to which extent 24 hour urine collections can be replaced by spot urine collections for diagnostic purposes. Whereas most steroid concentrations show poor correlation between 24 hour and spot urine collection, apparent enzyme activities show better correlation and defects in steroidogenic enzymes such as SRD5A2, CYP17A1, CYP21A2 and CYP11B1. We confirmed our findings in patient samples from our clinic.