{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T23:13:43Z","timestamp":1787786023994,"version":"build-2784847793"},"reference-count":11,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"2","license":[{"start":{"date-parts":[[2020,4,1]],"date-time":"2020-04-01T00:00:00Z","timestamp":1585699200000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,4]]},"abstract":"<jats:sec>\n            <jats:title>Background:<\/jats:title>\n            <jats:p>Therapeutic drug monitoring of antihypertensive drugs is being increasingly used to optimize treatment and to assess nonadherence. Separator gels are often used in blood collection tubes to facilitate serum or plasma separation from other blood constituents before analyses. Drug adsorption into the separator gel presents a possible pre-analytical cause of falsely low concentrations or false negative results.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Methods:<\/jats:title>\n            <jats:p>Drug-free blood from blood donors was spiked with therapeutic concentrations of 21 antihypertensive drugs, transferred to serum tubes with and without separator gel (Vacuette gel plastic tubes and plain serum plastic tubes, respectively), and centrifuged. Serum was collected immediately after centrifugation and after 24 and 72 hours of room temperature storage, samples were analyzed in triplicates using liquid chromatography\u2013mass spectrometry.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Results:<\/jats:title>\n            <jats:p>Serum samples collected immediately after centrifugation or 24 hours later, had the same drug concentrations in the gel and nongel tubes. After 72 hours of room temperature storage, verapamil and lercanidipine serum concentrations were 43% and 29%, respectively, lower in gel tubes than nongel tubes. Canrenone, diltiazem, and bendroflumethiazide showed between 10% and 20% concentration loss in gel tubes, compared with nongel tubes, with the 2 latter observed as unstable also in nongel tubes.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Conclusions:<\/jats:title>\n            <jats:p>Except for verapamil, lercanidipine, and canrenone, which showed substantial concentration loss in gel tubes, gel tubes may be used for therapeutic drug monitoring purposes for the most commonly used antihypertensive drugs. Transferring serum to gel-free containers immediately after centrifugation minimizes concentration loss; however, bendroflumethiazide and diltiazem are generally unstable at room temperature.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1097\/ftd.0000000000000708","type":"journal-article","created":{"date-parts":[[2019,10,14]],"date-time":"2019-10-14T15:39:45Z","timestamp":1571067585000},"page":"335-340","source":"Crossref","is-referenced-by-count":8,"title":["Stability of 21 Antihypertensive Drugs in Serum Collected in Standard (Nongel) Serum Tubes Versus Tubes Containing a Gel Separator"],"prefix":"10.1097","volume":"42","author":[{"given":"Solfrid","family":"Hegstad","sequence":"first","affiliation":[{"name":"Department of Clinical Pharmacology, St. Olav University Hospital; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olav","family":"Spigset","sequence":"additional","affiliation":[{"name":"Department of Clinical Pharmacology, St. Olav University Hospital; and"},{"name":"Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Arne","family":"Helland","sequence":"additional","affiliation":[{"name":"Department of Clinical Pharmacology, St. Olav University Hospital; and"},{"name":"Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","reference":[{"key":"R1-20230814","doi-asserted-by":"crossref","first-page":"2346","DOI":"10.1097\/HJH.0000000000001502","article-title":"Medication adherence among patients with apparent treatment-resistant hypertension: systematic review and meta-analysis","volume":"35","author":"Durand","year":"2017","journal-title":"J Hypertens."},{"key":"R2-20230814","doi-asserted-by":"crossref","first-page":"834","DOI":"10.1016\/j.jacc.2013.10.067","article-title":"Therapeutic drug monitoring facilitates blood pressure control in resistant hypertension","volume":"63","author":"Brinker","year":"2014","journal-title":"J Am Coll Cardiol."},{"key":"R3-20230814","doi-asserted-by":"crossref","first-page":"2411","DOI":"10.1097\/HJH.0000000000000346","article-title":"Potential cost-effectiveness of therapeutic drug monitoring in patients with resistant hypertension","volume":"32","author":"Chung","year":"2014","journal-title":"J Hypertens."},{"key":"R4-20230814","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1515\/CCLM.2000.045","article-title":"Suitability of collection tubes with separator gels for collecting and storing blood samples for therapeutic drug monitoring (TDM)","volume":"38","author":"Karppi","year":"2000","journal-title":"Clin Chem Lab Med."},{"key":"R5-20230814","doi-asserted-by":"crossref","first-page":"252","DOI":"10.1097\/MBC.0b013e32835b72ea","article-title":"Sodium citrate vacuum tubes validation: preventing preanalytical variability in routine coagulation testing","volume":"24","author":"Lima-Oliveira","year":"2013","journal-title":"Blood Coagul Fibrinolysis."},{"key":"R6-20230814","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1097\/00007691-200106000-00013","article-title":"Stability of therapeutic drugs in serum collected in vacutainer serum separator tubes containing a new gel (SST II)","volume":"23","author":"Bush","year":"2001","journal-title":"Ther Drug Monit."},{"key":"R7-20230814","doi-asserted-by":"crossref","first-page":"456","DOI":"10.1093\/ajcp\/101.4.456","article-title":"Absorption of therapeutic drugs by barrier gels in serum separator blood collection tubes. Volume- and time-dependent reduction in total and free drug concentrations","volume":"101","author":"Dasgupta","year":"1994","journal-title":"Am J Clin Pathol."},{"key":"R8-20230814","doi-asserted-by":"crossref","first-page":"427","DOI":"10.1097\/00007691-200008000-00011","article-title":"Time-dependent absorption of therapeutic drugs by the gel of the Greiner Vacuette blood collection tube","volume":"22","author":"Dasgupta","year":"2000","journal-title":"Ther Drug Monit."},{"key":"R9-20230814","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/j.cca.2016.08.014","article-title":"Where clinical chemistry meets medicinal chemistry. Systematic analysis of physico-chemical properties predicts stability of common used drugs in gel separator serum tubes","volume":"462","author":"Steuer","year":"2016","journal-title":"Clin Chim Acta."},{"key":"R10-20230814","doi-asserted-by":"crossref","first-page":"396","DOI":"10.1097\/FTD.0000000000000592","article-title":"Substantial differences in serum concentrations of psychoactive drugs measured in samples stored for two days or more on standard serum tubes versus serum tubes containing gel separators","volume":"41","author":"Wollmann","year":"2018","journal-title":"Ther Drug Monit."},{"key":"R11-20230814","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.jchromb.2018.04.038","article-title":"Quantification of 21 antihypertensive drugs in serum using UHPLC-MS\/MS","volume":"1089","author":"Gundersen","year":"2018","journal-title":"J Chromatogr B Analyt Technol Biomed Life Sci."}],"container-title":["Therapeutic Drug Monitoring"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.lww.com\/10.1097\/FTD.0000000000000708","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,8,14]],"date-time":"2023-08-14T22:38:03Z","timestamp":1692052683000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.lww.com\/10.1097\/FTD.0000000000000708"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,4]]},"references-count":11,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2020]]}},"URL":"https:\/\/doi.org\/10.1097\/ftd.0000000000000708","relation":{},"ISSN":["0163-4356"],"issn-type":[{"value":"0163-4356","type":"print"}],"subject":[],"published":{"date-parts":[[2020,4]]}}}