{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T15:25:44Z","timestamp":1788967544067,"version":"build-2803163510"},"reference-count":0,"publisher":"Oxford University Press (OUP)","issue":"2","content-domain":{"domain":["eje.bioscientifica.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2019,8]]},"abstract":"<jats:sec>\n<jats:title>Background<\/jats:title>\n<jats:p>Diagnosis and treatment of dysnatremia is challenging and further complicated by the pitfalls of different sodium measurement methods. Routinely used sodium measurements are the indirect (plasma\/serum) and direct (whole blood) ion-selective electrode (ISE) method, showing discrepant results especially in the setting of acute illness. Few clinicians are aware of the differences between the methods in clinically stable patients or healthy volunteers.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>Methods<\/jats:title>\n<jats:p>Data of 140 patients and 91 healthy volunteers undergoing osmotic stimulation with hypertonic saline infusion were analyzed. Sodium levels were measured simultaneously by indirect and direct ISE method before and at different time points during osmotic stimulation up to a sodium threshold of \u2265150\u2009mmol\/L. The primary outcome was the difference in sodium levels between the indirect and direct ISE method.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>Results<\/jats:title>\n<jats:p>878 sodium measurements were analyzed. Mean (<jats:sc>s.d.<\/jats:sc>) sodium levels ranged from 141\u2009mmol\/L (2.9) to 151\u2009mmol\/L (2.1) by the indirect ISE compared to 140\u2009mmol\/L (3) to 149\u2009mmol\/L (2.8) by the direct ISE method. The interclass correlation coefficient between the two methods was 0.844 (95% CI: 0.823\u20130.863). On average, measurements by the indirect ISE were 1.9\u2009mmol\/L (95% CI limits: \u22123.2 to 6.9) higher than those by the direct ISE method (<jats:italic>P<\/jats:italic>\u2009&lt;\u20090.001). The tendency of the indirect ISE method resulting in higher levels increased with increasing sodium levels.<\/jats:p>\n<\/jats:sec>\n<jats:sec>\n<jats:title>Conclusion<\/jats:title>\n<jats:p>Intra-individual sodium levels differ significantly between the indirect and direct ISE method also in the absence of acute illness. It is therefore crucial to adhere to the same method in critical situations to avoid false decisions due to measurement differences.<\/jats:p>\n<\/jats:sec>","DOI":"10.1530\/eje-19-0101","type":"journal-article","created":{"date-parts":[[2019,6,5]],"date-time":"2019-06-05T15:00:19Z","timestamp":1559746819000},"page":"193-199","update-policy":"https:\/\/doi.org\/10.1530\/crossmarkpolicy-1","source":"Crossref","is-referenced-by-count":18,"title":["The challenges of sodium measurements: indirect versus direct ion-selective method"],"prefix":"10.1093","volume":"181","author":[{"given":"Julie","family":"Refardt","sequence":"first","affiliation":[{"name":"1Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland"},{"name":"2 Department of Clinical Research, University of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Clara Odilia","family":"Sailer","sequence":"additional","affiliation":[{"name":"1Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland"},{"name":"2 Department of Clinical Research, University of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irina","family":"Chifu","sequence":"additional","affiliation":[{"name":"3Division of Endocrinology and Diabetes, Department of Internal Medicine I, University Hospital, University of W\u00fcrzburg, W\u00fcrzburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bettina","family":"Winzeler","sequence":"additional","affiliation":[{"name":"1Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland"},{"name":"2 Department of Clinical Research, University of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ingeborg","family":"Schnyder","sequence":"additional","affiliation":[{"name":"1Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland"},{"name":"2 Department of Clinical Research, University of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Fassnacht","sequence":"additional","affiliation":[{"name":"3Division of Endocrinology and Diabetes, Department of Internal Medicine I, University Hospital, University of W\u00fcrzburg, W\u00fcrzburg, Germany"},{"name":"4Central Laboratory, University Hospital W\u00fcrzburg, W\u00fcrzburg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wiebke","family":"Fenske","sequence":"additional","affiliation":[{"name":"5Department of Endocrinology and Nephrology, University of Leipzig, Leipzig, Germany"},{"name":"6Leipzig University Medical Center, IFB AdiposityDiseases, Leipzig, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mirjam","family":"Christ-Crain","sequence":"additional","affiliation":[{"name":"1Departments of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland"},{"name":"2 Department of Clinical Research, University of Basel, Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"_","family":"_","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","container-title":["European Journal of Endocrinology"],"original-title":[],"link":[{"URL":"https:\/\/eje.bioscientifica.com\/view\/journals\/eje\/181\/2\/EJE-19-0101.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/eje.bioscientifica.com\/view\/journals\/eje\/181\/2\/EJE-19-0101.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,2,14]],"date-time":"2023-02-14T16:13:07Z","timestamp":1676391187000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/ejendo\/article\/181\/2\/193\/6654061"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,8]]},"references-count":0,"journal-issue":{"issue":"2"},"URL":"https:\/\/doi.org\/10.1530\/eje-19-0101","relation":{},"ISSN":["0804-4643","1479-683X"],"issn-type":[{"value":"0804-4643","type":"print"},{"value":"1479-683X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,8]]}}}