Background Calculation of a urinary steroid metabolite ratio (uSMR) may be a useful method of improving diagnostic yield when investigating disorders of steroid hormone synthesis.
Objective and hypothesis To determine the range of uSMR and the relationship between the uSMR and the diagnostic outcome in abnormal cases.
Population/methods Ten ratios were calculated on steroid metabolite data previously analysed by GC-MS in urine samples from 544 patients under 18 years collected between 2008-2010.
Results Out of 544 patients, 337 (62%) were female, 189 (35%) were male and in 18 (3%) the sex was not documented. Indications for performing the test included adrenarche or XX virlisation in 239 (44%) cases and XY DSD in 68 (13%) cases. Median age at test was 7.4 years (r, 1 day,18 years) with 11%, 4%, 3%, 3%, 7%, 16%, 40%, 6%, 6% and 4% of tests performed in the following age bands, <1 week, 2 weeks-2 months, 3-5 months, 6-11 months, 1-3 years, 4-6 years, 7-9 years, 10-12 years, 13-15 years and 16-18 years, respectively. In 97 (18%) patients, one or more uSMR was above the 97th centile. The proportion of high uSMR according to the above age bands, was 0%, 0%, 2%, 11%, 33%, 6%, 16%, 8%, 7% and 17%, respectively. Out of these 97, case notes were reviewed in 28/32 cases from Glasgow. 5 (18%) patients had a confirmed steroid disorder (true positives), 8 (29%) had uSMR performed due to concerns such as ambiguous genitalia, premature adrenarche or cryptorchidism (possible true positives) and in the remaining 15 cases the tests were performed for a variety of reasons which resolved at a later stage (false positives).
Conclusions Applying simplified diagnostic ratios to urinary steroid profile data results in a yield of about 20% cases being abnormal. There is a need to improve the sensitivity and specificity of the uSMR and the reference ranges for these ratios.