New Strategies for Detecting Steroid Metabolic Disorders—Paneling vs Profiling

To the Editor: The steroid metabolic disorder 21-hydroxylase deficiency (21OHD)1 is increasingly being included in blood spot–based newborn-screening programs. Screening most commonly relies on 17-hydroxyprogesterone immunoassay, but it gives a high rate of false positives and may not provide differentiation from 2 other types of congenital adrenal hyperplasia—P450 oxidoreductase deficiency (PORD) and 11-hydroxylase deficiency. Koyama et al. recently reported in Clinical Chemistry reference cutoffs for 4 urinary steroid metabolites and derived ratios for differentiating 21OHD and PORD (1). Although this report was based on samples from 46 institutions, they did not specify whether samples were obtained during second-line screening after a finding of an increased 17-hydroxyprogesterone result in a blood spot screen. It is useful that the authors provided genotypes for all patients positive for one of …