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Published on: April 25, 2016
LC-MS/MS based determination of basal- and ACTH-stimulated plasma concentrations of 11 steroid hormones: implications
A E Kulle1, F G Riepe2, J Hedderich2
1Division of Pediatric Endocrinology and DiabetesDepartment of PediatricsInstitute of Medical Informatics and StatisticsUniversity Hospital Schleswig-Holstein, Christian-Albrechts University Kiel, Schwanenweg 20, D-24105 Kiel, Germany alexandra.kulle@uksh.de.
Objective:
Heterozygosity in 21-hydroxylase deficiency (21OHD) has been associated with hyperandrogenemic symptoms in children and adults. Moreover, the carrier status is mandatory for genetic counseling. We aimed at defining a hormonal parameter for carrier detection by mass spectrometry.
Design:
Eleven basal and ACTH-stimulated steroid hormones of heterozygous carriers of CYP21A2 mutations and control individuals were compared.
Method:
Hormones were determined in plasma samples by liquid chromatography tandem mass spectrometry (LC-MS/MS) in 58 carriers (35 males, 23 females, age range 6-78 years) and 44 random controls (25 males, 19 females, age range 8-58 years).
Results:
Heterozygotes could be identified best applying the 17-hydroxyprogesterone+21-deoxycortisol/cortisol×1000 ((17OHP+21S)/F×1000) equation 30 min after ACTH injection. An optimal cut-off value of 8.4 provided 89% sensitivity and specificity. Considering this data and a published frequency of heterozygotes of 1/50 to 1/61, the positive predictive value (PPV) of this cut-off is 12%. Of note, the negative predictive value (NPV) excluding heterozygosity in a given patient is 99.8%.
Conclusion:
Considering only marginal biochemical effects anticipated from heterozygosity, the stimulated ((17OHP+21S)/F×1000) identifies and excludes heterozygotes remarkably well. Nevertheless, LC-MS/MS cannot replace genetic testing, since sensitivity and specificity did not reach 100%. However, due to the considerably high NPV of the optimal cut-off and to a specificity of even 100% applying a cut-off higher than 14.7, hormonal assessment of heterozygosity can be of significant aid in conditions with limited access to genetic testing, as in some health care systems. The ((17OHP+21S)/F×1000) equation can guide diagnostic considerations in the differential diagnosis of hyperandrogenism.

