{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T22:16:06Z","timestamp":1786745766218,"version":"build-2736575974"},"reference-count":53,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2024,1,23]],"date-time":"2024-01-23T00:00:00Z","timestamp":1705968000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Intramural Research Program of the National Heart Lung and Blood Institute (NHLBI)"},{"name":"National Institutes of Health and Labcorp"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Lipoprotein X (LP-X) is an abnormal cholesterol-rich lipoprotein particle that accumulates in patients with cholestatic liver disease and familial lecithin\u2013cholesterol acyltransferase deficiency (FLD). Because there are no high-throughput diagnostic tests for its detection, a proton nuclear magnetic resonance (NMR) spectroscopy-based method was developed for use on a clinical NMR analyzer commonly used for the quantification of lipoproteins and other cardiovascular biomarkers. The LP-X assay was linear from 89 to 1615 mg\/dL (cholesterol units) and had a functional sensitivity of 44 mg\/dL. The intra-assay coefficient of variation (CV) varied between 1.8 and 11.8%, depending on the value of LP-X, whereas the inter-assay CV varied between 1.5 and 15.4%. The assay showed no interference with bilirubin levels up to 317 mg\/dL and was also unaffected by hemolysis for hemoglobin values up to 216 mg\/dL. Samples were stable when stored for up to 6 days at 4 \u00b0C but were not stable when frozen. In a large general population cohort (n = 277,000), LP-X was detected in only 50 subjects. The majority of LP-X positive cases had liver disease (64%), and in seven cases, had genetic FLD (14%). In summary, we describe a new NMR-based assay for LP-X, which can be readily implemented for routine clinical laboratory testing.<\/jats:p>","DOI":"10.3390\/molecules29030564","type":"journal-article","created":{"date-parts":[[2024,1,24]],"date-time":"2024-01-24T04:54:01Z","timestamp":1706072041000},"page":"564","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["A High-Throughput NMR Method for Lipoprotein-X Quantification"],"prefix":"10.3390","volume":"29","author":[{"given":"Erwin","family":"Garcia","sequence":"first","affiliation":[{"name":"Labcorp, Morrisville, NC 27560, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irina","family":"Shalaurova","sequence":"additional","affiliation":[{"name":"Labcorp, Morrisville, NC 27560, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steven P.","family":"Matyus","sequence":"additional","affiliation":[{"name":"Labcorp, Morrisville, NC 27560, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lita A.","family":"Freeman","sequence":"additional","affiliation":[{"name":"Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edward B.","family":"Neufeld","sequence":"additional","affiliation":[{"name":"Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0885-250X","authenticated-orcid":false,"given":"Maureen L.","family":"Sampson","sequence":"additional","affiliation":[{"name":"Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4274-3585","authenticated-orcid":false,"given":"Rafael","family":"Zubir\u00e1n","sequence":"additional","affiliation":[{"name":"Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9479-0741","authenticated-orcid":false,"given":"Anna","family":"Wolska","sequence":"additional","affiliation":[{"name":"Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alan T.","family":"Remaley","sequence":"additional","affiliation":[{"name":"Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA"},{"name":"Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James D.","family":"Otvos","sequence":"additional","affiliation":[{"name":"Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3917-592X","authenticated-orcid":false,"given":"Margery A.","family":"Connelly","sequence":"additional","affiliation":[{"name":"Labcorp, Morrisville, NC 27560, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,1,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1211","DOI":"10.1172\/JCI106085","article-title":"A lipoprotein characterizing obstructive jaundice. 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