Comparison of different preparation techniques of dried blood spot quality controls in newborn screening for congenital adrenal hyperplasia

PLoS One. 2021 May 20;16(5):e0252091. doi: 10.1371/journal.pone.0252091. eCollection 2021.

Abstract

In newborn screening, samples suspected for congenital adrenal hyperplasia (CAH), a potentially lethal inborn error of steroid biosynthesis, need to be confirmed using liquid chromatography-tandem mass spectrometry. Daily quality controls (QCs) for the 2nd-tier CAH assay are not commercially available and are therefore generally prepared within the laboratory. For the first time, we aimed to compare five different QC preparation approaches used in routine diagnostics for CAH on the concentrations of cortisol, 21-deoxycortisol, 11-deoxycortisol, 4-androstenedione and 17-hydroxyprogesterone in dried blood spots. The techniques from Prep1 to Prep5 were tested at two analyte concentrations by spiking aliquots of a steroid-depleted blood, derived from washed erythrocyte suspension and steroid-depleted serum. The preparation processes differed in the sequence of the preparation steps and whether freeze-thaw cycles were used to facilitate blood homogeneity. The five types of dried blood spot QCs were assayed and quantitated in duplicate on five different days using a single calibration row per day. Inter-assay variations less than 15% and concentrations within ±15% of the nominal values were considered acceptable. Results obtained by means of the four dried blood spot QC preparation techniques (Prep1, Prep2, Prep4 and Prep5) were statistically similar and remained within the ±15% ranges in terms of both reproducibility and nominal values. However, concentration results for Prep3 (spiking prior to three freeze-thaw cycles) were significantly lower than the nominal values in this setting, with differences exceeding the ±15% range in many cases despite acceptable inter-assay variations. These findings have implications for the in-house preparation of QC samples in laboratory developed tests for CAH, including 2nd-tier assays in newborn screening.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 17-alpha-Hydroxyprogesterone / blood
  • Adrenal Hyperplasia, Congenital / blood*
  • Adrenal Hyperplasia, Congenital / diagnosis*
  • Androstenedione / blood
  • Cortodoxone / blood
  • Dried Blood Spot Testing / methods*
  • Humans
  • Infant, Newborn
  • Neonatal Screening / methods*
  • Tandem Mass Spectrometry

Substances

  • Androstenedione
  • 21-deoxycortisol
  • 17-alpha-Hydroxyprogesterone
  • Cortodoxone

Grants and funding

This work was supported by the Hungarian-Romanian Cross-Border Cooperation Project (HU-RO) 0802/008 SCREENGEN. Article Processing Charges were covered by the Institutional Account Program of the University of Szeged, Szeged, Hungary (Open Access Fund, Grant number: 5121). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.