{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,21]],"date-time":"2026-10-21T04:42:33Z","timestamp":1792557753049,"version":"4.5.0"},"reference-count":13,"publisher":"Oxford University Press (OUP)","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,5]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Total serum vitamin B12 levels may not align with biomarkers of circulating active vitamin B12 or intracellular vitamin B12\u2013dependent metabolism. We estimated the population prevalence of marker-defined discordance among US adults and examined the influence of kidney function.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We analyzed National Health and Nutrition Examination Survey 2011-2012 data from 4318 adults with total vitamin B12, holotranscobalamin (holoTC), and methylmalonic acid (MMA) measurements and positive holoTC subsample weights. Low total vitamin B12 was defined as a level less than 200\u2009pg\/mL (148\u2009pmol\/L), low holoTC as a level less than 35\u2009pmol\/L, and elevated MMA as a level greater than 300\u2009nmol\/L. Analyses incorporated survey weights, strata, and primary sampling units.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Low total vitamin B12 was present in 1.7% of adults compared with low holoTC in 4.7% of adults and elevated MMA in 6.5% of adults. Overall, 9.7% of adults had low holoTC or elevated MMA. Among these adults, 60.6% had total vitamin B12 levels greater than 300\u2009pg\/mL. In a secondary integrated analysis, 2.2% (95% CI, 1.5%-2.9%) had a 3-marker combined vitamin B12 indicator less than \u22120.5. Methylmalonic acid\u2013based discordance increased with declining estimated glomerular filtration rate.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>Marker-defined low holoTC or elevated MMA was more common than low total vitamin B12. Methylmalonic acid should be interpreted in the context of kidney function.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/labmed\/lmag082","type":"journal-article","created":{"date-parts":[[2026,10,21]],"date-time":"2026-10-21T00:02:36Z","timestamp":1792540956000},"source":"Crossref","is-referenced-by-count":0,"title":["Vitamin B12 biomarker patterns and kidney function in US adults: National Health and Nutrition Examination Survey 2011-2012"],"prefix":"10.1093","volume":"57","author":[{"given":"Ashley M","family":"Foulkrod","sequence":"first","affiliation":[{"name":"Department of Internal Medicine, Womack Army Medical Center , Fort Bragg, NC,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elliott V","family":"Rebello","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery and Rehabilitation, Womack Army Medical Center , Fort Bragg, NC,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8971-1201","authenticated-orcid":false,"given":"Thomas A","family":"Beltran","sequence":"additional","affiliation":[{"name":"Department of Clinical Investigation, Womack Army Medical Center , Fort Bragg, NC,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erica L","family":"Gigas","sequence":"additional","affiliation":[{"name":"Center for Nursing Science and Inquiry, Womack Army Medical Center , Fort Bragg, NC,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carlos J","family":"Maldonado","sequence":"additional","affiliation":[{"name":"Department of Clinical Investigation, Womack Army Medical Center , Fort Bragg, NC,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,10,20]]},"reference":[{"key":"2026102100322670000_lmag082-B1","doi-asserted-by":"publisher","first-page":"17040","DOI":"10.1038\/nrdp.2017.40","article-title":"Vitamin B12 deficiency","volume":"3","author":"Green","year":"2017","journal-title":"Nat Rev Dis Primers"},{"key":"2026102100322670000_lmag082-B2","doi-asserted-by":"publisher","first-page":"1995S","DOI":"10.1093\/jn\/nxy201","article-title":"Biomarkers of Nutrition for Development (BOND): vitamin B-12 review","volume":"148","author":"Allen","year":"2018","journal-title":"J Nutr"},{"key":"2026102100322670000_lmag082-B3","doi-asserted-by":"publisher","first-page":"348S","DOI":"10.3945\/ajcn.111.013441","article-title":"Biomarkers of cobalamin (vitamin B-12) status in the epidemiologic setting: a critical overview of context, applications, and performance characteristics of cobalamin, methylmalonic acid, and 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