Pilot proficiency testing study for second tier congenital adrenal hyperplasia newborn screening

Area of Science:

• Biochemistry and Molecular Biology
• Clinical Diagnostics
• Public Health and Newborn Screening

Background:

• Congenital adrenal hyperplasia (CAH) arises from inherited defects in steroid biosynthesis.
• A pilot proficiency testing program using dried blood spots (DBS) was established for second-tier CAH screening via tandem mass spectrometry (MS/MS).

Purpose of the Study:

• To evaluate laboratory performance in second-tier CAH screening using MS/MS.
• To assess materials and methodologies for DBS-based CAH testing.
• To improve the accuracy and consistency of newborn screening for CAH.

Main Methods:

• Utilized the ratio of 17-α-hydroxyprogesterone (17-OHP), androstenedione (4-AD), and cortisol as CAH indicators.
• Prepared DBS specimens with varying steroid concentrations for proficiency testing.
• Laboratories analyzed blind-coded DBS specimens and reported results for evaluation.

Main Results:

• Participant quantitative results showed minor analytical method variations.
• Analyte recoveries demonstrated significant improvements: 17-OHP from 81% to 107%, cortisol from 61.9% to 89.5%.
• Androstenedione (4-AD) recoveries showed a decrease from 184% to 68%.

Conclusions:

• Participation in the CAH proficiency testing program led to better analyte recoveries and sample preparation.
• NSQAP's services highlight the necessity of ongoing surveillance for harmonized, high-performance newborn screening globally.
• Continuous improvement and standardization are crucial for sustained laboratory performance in CAH screening.