Rapid monitoring assay of congenital adrenal hyperplasia with microbore high-performance liquid chromatography/electrospray ionization tandem mass spectrometry from dried blood spots

17-Hydroxyprogesterone (17OHP) is the most important plasma parameter for diagnosing and monitoring congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency. A rapid, simple, and specific method based on microbore high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (mu -HPLC/ESI-MS/MS) was developed to determine the presence of 17OHP on dried filter-paper blood samples from patients with CAH caused by 21-hydroxylase deficiency. 17OHP from dried blood spots formed by the action of Girard reagent P (Girl?) turned out to be a water-soluble hydrazone complex. Derivatization with Girl? led to higher ESI sensitivity for 17OHP. The LC/MS/MS detection of GirP-derivatized 17OHP (GirP-17OHP) was rapid (<3 min). The method is repeatable and reproducible, with CVs <7% and 12%, respectively. This new method was used for direct determination of 17OHP in dried blood specimens obtained from abnormal children and infants of various ages with a detection limit of 10 ng/mL (similar to 12 muL blood). The method described allows for rapid and reliable measurements of 17OHP in dried blood specimens from patients affected by CAH. Copyright (C) 2001 John Wiley & Sons, Ltd.