{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T12:31:39Z","timestamp":1790857899679,"version":"4.1.0"},"reference-count":37,"publisher":"Oxford University Press (OUP)","issue":"3","license":[{"start":{"date-parts":[[2026,2,28]],"date-time":"2026-02-28T00:00:00Z","timestamp":1772236800000},"content-version":"vor","delay-in-days":1,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100004319","name":"Pfizer","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100004319","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100002999","name":"Dutch Ministry of Health, Welfare and Sport","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100002999","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100005075","name":"University Medical Center Groningen","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100005075","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001721","name":"University of Groningen","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001721","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,3,4]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Accurate interpretation of insulin-like growth factor-1 (IGF1) requires both analytically robust measurement and appropriate reference data. Most available IGF1 normative datasets are based on ligand-binding assays (LBA), limiting their applicability to liquid chromatography-tandem mass spectrometry (LC-MS\/MS) methods that provide higher analytical specificity.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To evaluate the clinical performance of an in-house developed LC-MS\/MS IGF1 assay in combination with a method-matched normative dataset derived from the Dutch Lifelines cohort, and to compare it with a commonly used LBA.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Paired IGF1 results (n = 2057) were obtained using LC-MS\/MS and the IDS iSYS LBA. Standard deviation scores (SDS) were calculated using assay-specific normative datasets. Agreement was assessed by regression, Bland-Altman, and weighted Cohen's \u03ba analyses. Clinical validity was evaluated by comparing extreme SDS values with diagnostic categories adjudicated by endocrinologists.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The LC-MS\/MS method showed a proportional bias of \u221227% versus IDS iSYS and yielded symmetrically distributed SDS around zero, whereas IDS iSYS results were positively skewed. Categorical agreement was fair (\u03ba = 0.39). LC-MS\/MS-derived SDS corresponded more closely with clinical diagnoses across adult and pediatric groups, including acromegaly, growth hormone (GH) deficiency, and GH replacement therapy.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Our LC-MS\/MS IGF1 assay integrated with its own population-based normative dataset demonstrated superior alignment with clinical assessment compared with LBA results. In our setting, this method provides a clinically reliable benchmark for IGF1 interpretation and may serve as a reference for IGF1 harmonization and broader adoption of the Lifelines normative dataset in routine endocrinology.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/ejendo\/lvag040","type":"journal-article","created":{"date-parts":[[2026,2,25]],"date-time":"2026-02-25T12:45:13Z","timestamp":1772023513000},"page":"347-356","source":"Crossref","is-referenced-by-count":1,"title":["Clinical performance of an IGF1 LC-MS\/MS assay and associated normative dataset in routine endocrinology"],"prefix":"10.1093","volume":"194","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9379-2219","authenticated-orcid":false,"given":"Michel J","family":"Vos","sequence":"first","affiliation":[{"name":"Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen , Groningen ,","place":["The 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