{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T04:33:28Z","timestamp":1789619608669,"version":"build-2803163510"},"reference-count":25,"publisher":"Oxford University Press (OUP)","issue":"2","license":[{"start":{"date-parts":[[2026,1,23]],"date-time":"2026-01-23T00:00:00Z","timestamp":1769126400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,3,5]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Methotrexate (MTX), a synthetic antimetabolite and folic acid antagonist, has become a cornerstone in the management of malignant diseases. However, MTX toxicity can be severe and potentially life-threatening, especially with high-dose regimens used in oncology. Given its narrow therapeutic index, precise monitoring of MTX levels is critical to optimize efficacy while minimizing toxicity.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We validated the performance of the Roche ONLINE therapeutic drug monitoring (TDM) Methotrexate Assay on Cobas c502 and Cobas pro c503 platforms across 2 clinical sites, focusing on key analytical parameters such as linearity, accuracy, precision, dilution, carryover, and method comparison.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The assay was linear across the analytical measurement interval (AMI) of 0.04\u20131.2\u2005\u00b5mol\/L. No significant carryover was observed (i.e., &amp;lt;5% bias). Automatic and manual dilutions demonstrated &amp;lt;10% bias, and the coefficients of variation (CVs) for precision and percentage bias for accuracy were &amp;lt;10%. A method comparison using 40 patient samples showed a strong correlation between the Roche and ARK MTX assays, with a Deming regression slope of 0.9634, an intercept of \u22120.0095, and Pearson correlation coefficient (r) = 0.9935, with a mean percentage difference (%Bias) of \u221212. Comparison with LC-MS\/MS demonstrated high agreement for both assays. The ARK assay yielded a slope of 0.8873, an intercept of 0.0145, r = 0.9978, and %Bias of \u22126, while the Roche assay yielded a slope of 0.8541, an intercept of 0.0047, r = 0.9919, and %Bias of \u221218.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The Roche ONLINE TDM MTX assay is a robust and clinically adequate method for methotrexate quantification and therapeutic drug monitoring.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/jalm\/jfaf189","type":"journal-article","created":{"date-parts":[[2025,11,20]],"date-time":"2025-11-20T13:31:50Z","timestamp":1763645510000},"page":"320-329","source":"Crossref","is-referenced-by-count":1,"title":["Multi-Site Validation of a Newly FDA-Cleared Automated Methotrexate Immunoassay for Therapeutic Drug Monitoring"],"prefix":"10.1093","volume":"11","author":[{"given":"Shaimaa","family":"Maher","sequence":"first","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles , Los Angeles, CA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vincent","family":"Buggs","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles , Los Angeles, CA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Patrick","family":"Ravelo","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles , Los Angeles, CA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4042-5316","authenticated-orcid":false,"given":"Lu","family":"Song","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles , Los Angeles, CA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Imir G","family":"Metushi","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles , Los Angeles, CA ,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,1,23]]},"reference":[{"key":"2026030508524380600_jfaf189-B1","first-page":"2060","article-title":"Anticancer effects of methotrexate in combination with \u03b1-tocopherol and \u03b1-tocopherol 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