{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T03:53:00Z","timestamp":1790221980242,"version":"4.1.0"},"reference-count":38,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2024,6,12]],"date-time":"2024-06-12T00:00:00Z","timestamp":1718150400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Manfred-Donike Institute for Doping Analysis (Cologne, Germany)"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Metabolites"],"abstract":"<jats:p>Relative energy deficiency in sport (RED-S) is a condition that arises from persistent low energy availability (LEA), which affects the hypothalamic\u2013pituitary axis and results in alterations of several hormones in both male and female athletes. As frequent blood hormone status determinations using venipuncture are rare in sports practice, microsampling offers promising possibilities for preventing and assessing RED-S. Therefore, this study aimed at developing a liquid chromatography\u2013high-resolution tandem mass spectrometry (LC-HRMS\/MS) method for quantifying relevant steroids and thyroid hormones in 30 \u03bcL of capillary blood obtained using Mitra\u00ae devices with volumetric absorptive microsampling technology (VAMS\u00ae). The results of the study showed that all validation criteria were met, including a storage stability of more than 28 days in a frozen state (\u221218 \u00b0C) and 14 days at room temperature (20 \u00b0C). The validated assay provided precise (&lt;12%) and accurate (&lt;13%) results for all the target analytes. Furthermore, as a proof of concept, autonomously collected VAMS\u00ae samples from 50 female and male, healthy, active adults were analyzed. The sensitivity of all analytes was adequate to quantify the decreased hormone concentrations in the RED-S state, as all authentic samples could be measured accordingly. These findings suggest that self-collected VAMS\u00ae samples offer a practical opportunity for regular hormone measurements in athletes and can be used for early RED-S assessment and progress monitoring during RED-S recovery.<\/jats:p>","DOI":"10.3390\/metabo14060328","type":"journal-article","created":{"date-parts":[[2024,6,12]],"date-time":"2024-06-12T06:47:30Z","timestamp":1718174850000},"page":"328","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Development of an LC-HRMS\/MS Method for Quantifying Steroids and Thyroid Hormones in Capillary Blood: A Potential Tool for Assessing Relative Energy Deficiency in Sport (RED-S)"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-5834-1865","authenticated-orcid":false,"given":"Chiara","family":"Tuma","sequence":"first","affiliation":[{"name":"Institute of Biochemistry, Center of Preventive Doping Research, German Sport University Cologne, 50933 Cologne, Germany"},{"name":"German Research Centre of Elite Sports (Momentum), German Sport University Cologne, 50933 Cologne, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1199-0743","authenticated-orcid":false,"given":"Andreas","family":"Thomas","sequence":"additional","affiliation":[{"name":"Institute of Biochemistry, Center of Preventive Doping Research, German Sport University Cologne, 50933 Cologne, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hans","family":"Braun","sequence":"additional","affiliation":[{"name":"Institute of Biochemistry, Center of Preventive Doping Research, German Sport University Cologne, 50933 Cologne, Germany"},{"name":"German Research Centre of Elite Sports (Momentum), German Sport University Cologne, 50933 Cologne, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mario","family":"Thevis","sequence":"additional","affiliation":[{"name":"Institute of Biochemistry, Center of Preventive Doping Research, German Sport University Cologne, 50933 Cologne, Germany"},{"name":"European Monitoring Center for Emerging Doping Agents (EuMoCEDA), 50933 Cologne, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,6,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s00421-020-04516-0","article-title":"Low Energy Availability: History, Definition and Evidence of Its Endocrine, Metabolic and Physiological Effects in Prospective Studies in Females and Males","volume":"121","author":"Areta","year":"2021","journal-title":"Eur. 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