Comparison of multiple steroid concentrations in serum and dried blood spots throughout the day of patients with congenital adrenal hyperplasia

Background/Aim: Periodic measurement of plasma concentrations of cortisol precursors on a clinic visit may be of limited value in patients with congenital adrenal hyperplasia because it does not reflect a patient's circadian patterns of adrenal steroid secretion. Steroid profiling in dried blood spots (DBS) may allow for more frequent and sensitive monitoring. Methods: We compared the agreement between 17α-hydroxyprogesterone (17-OHP) and androstenedione (D4A) levels determined from DBS samples and concurrently collected serum samples. Blood was drawn from 9 congenital adrenal hyperplasia patients every 4 h over a 24-hour period. Serum and DBS steroid levels were measured by liquid chromatography tandem mass spectrometry. Results: DBS determinations of 17-OHP overestimated corresponding serum levels (mean difference 1.67 ng/ml), and underestimated D4A serum levels (mean difference 0.84 ng/ml). However, the DBS assay yielded excellent agreement (97%) with serum 17-OHP, but did considerably poorer for D4A (31%). Conclusions: Our results indicate an excellent agreement between DBS and serum 17-OHP measurements to identify the peaks and troughs associated with an individual's circadian pattern. Larger-scale studies are required to evaluate the utility of DBS for home monitoring and to determine if more frequent monitoring leads to improved clinical outcomes.