Analytical bias of automated immunoassays for six serum steroid hormones assessed by LC-MS/MS.

Željko Debeljak,Ivana Marković,Iva Lukić,Sanja Mandić,Dario Mandić,Vesna Horvat,Vatroslav Šerić,Jasna Pavela

doi:10.11613/bm.2020.030701

Abstract

IntroductionThere is a growing amount of evidence showing the significant analytical bias of steroid hormone immunoassays, but large number of available immunoassays makes conduction of a single comprehensive study of this issue hardly feasible. Aim of this study was to assess the analytical bias of six heterogeneous immunoassays for serum aldosterone, cortisol, dehydroepiandrosterone sulphate (DHEAS), testosterone, 17-hydroxyprogesterone (OHP) and progesterone using the liquid chromatography coupled to the tandem mass spectrometry (LC-MS/MS).Materials and methodsThis method comparison study included 49 serum samples. Testosterone, DHEAS, progesterone and cortisol immunoassays were performed on the Abbott Architect i2000SR or Alinity i analysers (Abbott Diagnostics, Chicago, USA). DiaSorin’s Liaison (DiaSorin, Saluggia, Italy) and DIAsource’s ETI-Max 3000 analysers (DIAsource ImmunoAssays, Louvain-La-Neuve, Belgium) were chosen for aldosterone and OHP immunoassay testing, respectively. All immunoassays were evaluated against the LC-MS/MS assay relying on the commercial kit (Chromsystems, Gräfelfing, Germany) and LCMS-8050 analyser (Shimadzu, Kyoto, Japan). Analytical biases were calculated and method comparison was conducted using weighted Deming regression analysis.ResultsDepending on the analyte and specific immunoassay, mean relative biases ranged from -31 to + 137%. Except for the cortisol, immunoassays were positively biased. For none of the selected steroids slope and intercept 95% confidence intervals simultaneously contained 0 and 1, respectively.ConclusionsEvaluated immunoassays failed to satisfy requirements for methods’ comparability and produced significant analytical biases in respect to the LC-MS/MS assay, especially at low concentrations.

Highlights

There is a growing amount of evidence showing the significant analytical bias of steroid hormone immunoassays, but large number of available immunoassays makes conduction of a single comprehensive study of this issue hardly feasible
Depending on the analyte and specific immunoassay, mean relative biases ranged from -31 to + 137%
In the classical congenital adrenal hyperplasia (CAH), falsely elevated cortisol may be due to the cross-reactivity with 21-deoxycortisol, while in the pregnancy pregnenolone sulphate interferes with the dehydroepiandrosterone sulphate (DHEAS) measurement

Summary

Introduction

There is a growing amount of evidence showing the significant analytical bias of steroid hormone immunoassays, but large number of available immunoassays makes conduction of a single comprehensive study of this issue hardly feasible. Aim of this study was to assess the analytical bias of six heterogeneous immunoassays for serum aldosterone, cortisol, dehydroepiandrosterone sulphate (DHEAS), testosterone, 17-hydroxyprogesterone (OHP) and progesterone using the liquid chromatography coupled to the tandem mass spectrometry (LC-MS/MS). Immunoassays are widely used for quantification of different serum steroid hormones. This analytical approach can be automated which, in turn, reduces the turn-around-time and staff requirements. While the immunoassays for protein quantifications are prone to different types of interferences, immunoassays intended for determinations of small biomolecules like steroids are affected primarily by the lack of selectivity [2,3]. In the classical congenital adrenal hyperplasia (CAH), falsely elevated cortisol may be due to the cross-reactivity with 21-deoxycortisol, while in the pregnancy pregnenolone sulphate interferes with the dehydroepiandrosterone sulphate (DHEAS) measurement.

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Conclusion