{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T16:10:57Z","timestamp":1788883857962,"version":"build-2803163510"},"reference-count":22,"publisher":"American Veterinary Medical Association (AVMA)","license":[{"start":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T00:00:00Z","timestamp":1788825600000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ajvr"],"published-print":{"date-parts":[[2026,9,8]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec id=\"sc_a1\">\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To compare itraconazole therapeutic drug monitoring (TDM) results by culture-based bioassay versus liquid chromatography\u2013mass spectrometry (LC-MS) in dogs with blastomycosis and determine how the choice of assay might influence dosage adjustments.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sc_a2\">\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This was a retrospective study. Ninety-seven samples from 14 client-owned dogs with blastomycosis were collected from October 2023 through May 2025 and analyzed by bioassay and 3 LC-MS\u2013derived variables: itraconazole alone (ITZ), the hydroxyitraconazole metabolite, and the sum of itraconazole and hydroxyitraconazole. Linear mixed models were used to assess the relationship between dosage and itraconazole concentration by bioassay and LC-MS and between bioassay and the LC-MS variables. A clinical concordance grid was used to assess agreement between bioassay and ITZ by LC-MS regarding dosage-adjustment decisions.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sc_a3\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      There was no significant association between itraconazole dosage and serum concentration. There was a significant relationship between concentration by bioassay versus LC-MS (\n                      <jats:italic>P<\/jats:italic>\n                      &lt; .01). The association was weak for ITZ (\n                      <jats:italic>r<\/jats:italic>\n                      <jats:sup>2<\/jats:sup>\n                      = 0.40) but was moderate for the hydroxyitraconazole metabolite (\n                      <jats:italic>r<\/jats:italic>\n                      <jats:sup>2<\/jats:sup>\n                      = 0.48) and the sum of itraconazole and hydroxyitraconazole (\n                      <jats:italic>r<\/jats:italic>\n                      <jats:sup>2<\/jats:sup>\n                      = 0.48). Of 97 samples, 62 (64%) demonstrated agreement in dosage adjustment, and 35 (36%) did not.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sc_a4\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Dosage of itraconazole does not reliably predict serum itraconazole concentration, requiring TDM for effective dosage-adjustment decisions. Bioassay and LC-MS are not interchangeable assays for itraconazole TDM in dogs.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sc_a5\">\n                    <jats:title>Clinical Relevance<\/jats:title>\n                    <jats:p>TDM should be considered during long-term itraconazole therapy to optimize dose. A single assay method (bioassay or LC-MS) should be used consistently throughout the entire course of antifungal therapy.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.2460\/ajvr.26.07.0303","type":"journal-article","created":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T15:48:18Z","timestamp":1788882498000},"page":"1-10","source":"Crossref","is-referenced-by-count":0,"title":["Bioassay and liquid chromatography\u2013mass spectrometry are not equivalent in itraconazole therapeutic drug monitoring in dogs"],"prefix":"10.2460","author":[{"given":"Kelly","family":"Hearn","sequence":"first","affiliation":[{"name":"Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL"},{"name":"Department of Clinical Medicine, College of Veterinary Medicine, Oregon State University, Corvallis, OR"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6449-2812","authenticated-orcid":true,"given":"Arnon","family":"Gal","sequence":"additional","affiliation":[{"name":"Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2225-5122","authenticated-orcid":true,"given":"Nathan P.","family":"Wiederhold","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Fungus Testing Laboratory, School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sunam","family":"Park","sequence":"additional","affiliation":[{"name":"Department of Pathology and Laboratory Medicine, Fungus Testing Laboratory, School of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6523-4033","authenticated-orcid":true,"given":"Andrew","family":"Hanzlicek","sequence":"additional","affiliation":[{"name":"MiraVista Diagnostics, Indianapolis, IN"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3021-5075","authenticated-orcid":true,"given":"Jennifer M.","family":"Reinhart","sequence":"additional","affiliation":[{"name":"Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1272","reference":[{"issue":"4","key":"B1","series-title":"J Am Anim Hosp Assoc","first-page":"195","article-title":"Comparison of compounded, generic, and innovator-formulated itraconazole in dogs and cats","volume":"54","author":"Renschler J","year":"2018","unstructured":"Renschler J, Albers A, Sinclair-Mackling H, Wheat LJ. Comparison of compounded, generic, and innovator-formulated itraconazole in dogs and cats. J Am Anim Hosp Assoc. 2018;54(4):195\u2013200. doi:10.5326\/JAAHA-MS-6591"},{"issue":"1","key":"B2","series-title":"J Vet Intern Med","first-page":"aalag029","article-title":"Therapeutic drug monitoring of itraconazole in treatment of blastomycosis in dogs","volume":"40","author":"Reinhart JM","year":"2026","unstructured":"Reinhart JM, Leduc F, Hanzlicek A, et al. Therapeutic drug monitoring of itraconazole in treatment of blastomycosis in dogs. J Vet Intern Med. 2026;40(1):aalag029. doi:10.1093\/jvimsj\/aalag029"},{"issue":"1","key":"B3","series-title":"Antimicrob Agents Chemother","first-page":"424","article-title":"A reference laboratory experience of clinically achievable voriconazole, posaconazole, and itraconazole concentrations within the bloodstream and cerebral spinal fluid","volume":"58","author":"Wiederhold NP","year":"2014","unstructured":"Wiederhold NP, Pennick GJ, Dorsey SA, et al. A reference laboratory experience of clinically achievable voriconazole, posaconazole, and itraconazole concentrations within the bloodstream and cerebral spinal fluid. Antimicrob Agents Chemother. 2014;58(1):424\u2013431. doi:10.1128\/AAC.01558-13"},{"issue":"4","key":"B4","series-title":"Antimicrob Agents Chemother","first-page":"e02353-20","article-title":"Variability of hydroxy-itraconazole in relation to itraconazole bloodstream concentrations","volume":"65","author":"Wiederhold NP","year":"2021","unstructured":"Wiederhold NP, Schwartz IS, Patterson TF, Thompson GR 3rd. Variability of hydroxy-itraconazole in relation to itraconazole bloodstream concentrations. Antimicrob Agents Chemother. 2021;65(4):e02353-20. doi:10.1128\/AAC.02353-20"},{"issue":"suppl 1","key":"B5","series-title":"Mycoses","first-page":"67","article-title":"The clinical pharmacokinetics of itraconazole: an overview","volume":"32","author":"Heykants J","year":"1989","unstructured":"Heykants J, Van Peer A, Van de Velde V, et al. The clinical pharmacokinetics of itraconazole: an overview. Mycoses. 1989;32(suppl 1):67\u201387. doi:10.1111\/j.1439-0507.1989.tb02296.x"},{"issue":"3","key":"B6","series-title":"J Antimicrob Chemother","first-page":"371","article-title":"Antifungal activity of itraconazole compared with hydroxy-itraconazole in vitro","volume":"45","author":"Odds FC","year":"2000","unstructured":"Odds FC, Bossche HV. Antifungal activity of itraconazole compared with hydroxy-itraconazole in vitro. 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Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events (VCOG-CTCAE v2) following investigational therapy in dogs and cats. Vet Comp Oncol. 2021;19(2):311\u2013352. doi:10.1111\/vco.12677"},{"key":"B9","unstructured":"General chapters <795> pharmaceutical compounding \u2013 nonsterile preparations. USP. May 1, 2020. Accessed September 15, 2025. https:\/\/www.uspnf.com\/sites\/default\/files\/usp_pdf\/EN\/USPNF\/revisions\/gc-795-rb-notice-20200424.pdf"},{"key":"B10","year":"2026","unstructured":"Itraconazole levels. MiraVista. 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