J Clin Lab Anal. 2018;32:e22286. wileyonlinelibrary.com/journal/jcla
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© 2017 Wiley Periodicals, Inc.
Reassessment of the Access Testosterone chemiluminescence
assay and comparison with LC- MS method
| Mara Matteucci
| Elisa Meneghetti
| Rudina Ndreu
U.O.C. Laboratorio Analisi, Laboratory
Eureka srl - Lab Division, Chiaravalle (AN),
CNR Clinical Physiology Institute, Pisa, Italy
Ruggero Dittadi, Laboratory Analysis Unit,
Department of Clinical Pathology, Ospedale
Aim of the study: To reassess the imprecision and Limit of Quantitation, to evaluate the
cross- reaction with dehydroepiandrosterone- sulfate (DHEAS), the accuracy toward liquid
chromatography-mass spectrometry (LC-MS) and the reference interval of the Access
Testosterone method, performed by DxI immunoassay platform (Beckman Coulter).
Material and Methods: Imprecision was evaluated testing six pool samples assayed in
20 different run using two reagents lots. The cross- reaction with DHEAS was studied
both by a displacement curve and by spiking DHEAS standard in two serum samples
External Quality Assurance (EQA) scheme. The reference interval was verified by an
indirect estimation on 2445 male and 2838 female outpatients.
Results: The imprecision study showed a coefficient of variation (CV) between 2.7%
and 34.7% for serum pools from 16.3 and 0.27 nmol/L. The value of Limit of
Quantitation at 20% CV was 0.53 nmol/L. The DHEAS showed a cross- reaction of
of immunoassay vs LC-MS (Passing-Bablock equations: DxI=−0.24+0.906 LCMS in
serum samples and DxI=−0.299+0.981LCMSinEQAsamples).Theverificationofref-
male over 14 years and <0.5- 2.78 nmol/L for female subjects, in accord with the refer-
ence intervals reported by the manufacturer.
Conclusions: The Access Testosterone method could be considered an adequately
reliable tool for the testosterone measurement.
cross-reaction, DxI platform, immunoassay method, liquid chromatography-mass spectrometry,
1 | INTRODUCTION
Testosterone is the principal androgen hormone, and is produced
mainly in the male by the Leydig testis cells. It is also present in the
female as intermediate metabolite of the estrogens synthesis and de-
rived by androstenedione by peripheral conversion.
The testosterone determination can be used in the delayed puberty,
in primary or secondary hypogonadism and in some female endocrine
disorders, as hirsutism, virilization and/or in polycystic ovarian syndrome.
It is worth noting that, so far, no reliable routine methods for direct
determination of active testosterone free form are available,
and it is
to date suggested the estimate of bioavailable testosterone through
total testosterone determination and the mainly binding protein, the
Sex Hormone Binding Globulin.
However, the commonly used im-
munometric assays for testosterone measurement could show limited
sensitivity and accuracy at clinically relevant levels.
One of the reasons of these analytical drawbacks could
be interferences from other steroid hormones. In particular,