Evaluation of a multiplex liquid chromatography-tandem mass spectrometry method for congenital adrenal hyperplasia in pediatric patients

Multiplexed adrenal steroid measurement provides critical diagnostic information for patients with congenital adrenal hyperplasia (CAH) as confirmation of newborn screening (NBS) or as initial diagnosis. This study reports the implementation of an adrenal steroid profiling method with a turnaround time (TAT) of less than 24 h using liquid chromatography and tandem-mass spectrometry (LC-MS/MS). A lab-developed multiplexed LC-MS/MS assay was used to quantify levels of 11-deoxycortisol, cortisol, 17-hydroxy-progesterone (17-OHP), androstenedione, and testosterone. Intra and interassay imprecision were found to be < 10%. Comparison with a reference laboratory revealed < 20% bias for all 5 analytes and Deming correlation coefficients > 0.990. Linearity ranges were established from the lowest to upper limit calibrator concentrations with 100- to 800-fold maximum dilution. Run to run carryover was < 0.1%, and acceptable matrix effect was observed (i.e., ion suppression enhancement < 15%). Compared to serum samples, ethylenediaminetetraacetic acid (EDTA) and heparin plasma had large positive bias in the measurement of 11-deoxycortisol (62.2% and 60.2%, respectively) and androstenedione (43.8% and 33.2%, respectively), while cortisol, 17-OHP and testosterone showed less than 20% bias between sample types. Hemoglobin, bilirubin, or triglyceride interference decreased 11-deoxycortisol measurement in EDTA plasma (-19.3%, -25.6%, and -25.0%, respectively). Lipemia increased the measurement of testosterone by 28.9%. In summary, our multiplexed LC-MS/MS method provided highly sensitive and specific measurement of adrenal steroids. EDTA, heparin, hemolysis, icterus and/or lipemia may significantly impact assay results and should be avoided. This method provides an effective strategy for improving TAT in CAH testing and confirmation of NBS results.