Publications by authors named "Rachel Aakeroy"

4 Publications

  • Page 1 of 1

Serum or Plasma for Quantification of Direct Oral Anticoagulants?

Ther Drug Monit 2022 08 20;44(4):578-584. Epub 2022 Jan 20.

Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway.

Background: Direct oral anticoagulants are increasingly replacing vitamin K antagonists for prevention of stroke in patients with atrial fibrillation, partly owing to the lack of a need for routine monitoring. Therapeutic drug monitoring may still be warranted under certain circumstances. It is generally assumed that serum and plasma can be interchangeably used for this purpose. The aim of this study was to investigate possible differences between the serum, citrate-plasma, and ethylenediaminetetraacetic acid (EDTA)-plasma concentrations of apixaban and rivaroxaban in a larger patient group and their relation to factor X measurements.

Methods: Plasma and serum samples were drawn during the same venipuncture from patients treated with apixaban or rivaroxaban. Drug levels were measured using ultrahigh-performance liquid chromatography combined with tandem mass spectrometry. Three sample matrices were obtained from 8 healthy volunteers for measurement of factor X antigen and activity.

Results: Mean concentrations of apixaban and rivaroxaban were 16.8% and 36.6% higher in serum than in citrate-plasma, respectively (both P < 0.001). The corresponding differences in serum versus EDTA-plasma were 4.5% for apixaban and 13.1% for rivaroxaban (both P < 0.001). Factor X antigen measurements in citrate-plasma, EDTA-plasma, serum with clot activator, and serum without additives yielded comparable results, and factor X activity was significantly higher in serum than in plasma.

Conclusions: Apixaban and rivaroxaban concentrations were significantly higher in serum than in plasma. The difference was more pronounced with rivaroxaban and was larger between serum and citrate-plasma than between serum and EDTA-plasma. Higher factor X activity in serum may explain the observed concentration differences. The choice of matrix is, thus, important when interpreting therapeutic drug monitoring results and in research involving analyses of direct oral anticoagulants. The authors recommend citrate-plasma as the preferred matrix.
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August 2022

Severe Neurological Sequelae after a Recreational Dose of LSD.

J Anal Toxicol 2021 Aug;45(7):e1-e3

Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.

A young man with an unremarkable medical history suffered a seizure with subsequent cardiorespiratory arrest and severe neurological sequelae after ingesting a blotter. Analysis of a similar blotter and a serum sample obtained 3 h after the event detected lysergic acid diethylamide (LSD) at an amount of 300 µg in the blotter and at a concentration of 4.0 ng/mL (12.4 nmol/L) in the serum. No other drugs were present in concentrations which may confer significant effects. In addition, no individual traits which would make the patient particularly susceptible to adverse LSD effects have subsequently been identified. This suggests that LSD may confer toxic effects in previously healthy individuals.
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August 2021

[New biomarkers for assesing alcohol consumption].

Tidsskr Nor Laegeforen 2016 Oct 25;136(19):1643-1647. Epub 2016 Oct 25.

Avdeling for klinisk farmakologi St. Olavs hospital og Institutt for laboratoriemedisin, barne- og kvinnesykdommer Norges teknisk-naturvitenskapelige universitet.

Alcohol abuse has significant medical, social and socioeconomic consequences. Alcohol biomarkers may serve as a useful tool in identifying individuals with excessive alcohol consumption in medical as well as medico-legal contexts.
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October 2016

Incidence of inflammatory bowel disease in Malta between 1993 and 2005: a retrospective study.

Inflamm Bowel Dis 2008 Apr;14(4):550-3

Department of Gastroenterology, St. Luke's University Hospital, Malta.

Background: The primary aim of the study was to estimate the incidence of Crohn's disease (CD) and ulcerative colitis (UC), collectively known as inflammatory bowel disease (IBD), in Malta in a well-defined population during a 13-year study period.

Methods: Diagnostic criteria for CD and UC were defined. A diagnosis of IBD was obtained from the histopathology reports at St. Luke's Hospital, Malta, between January 1993 and December 2005. The date of diagnosis was defined as the date of the first histopathology report revealing signs of IBD.

Results: Incidence rates were standardized using the direct method on the European Standard Population. The mean incidence of UC in males was 8.16 per 100,000 per year and for females was 7.59 per 100,000 per year, while that for CD in males was 0.96 per 100,000 per year and for females 1.622 per 100,000 per year. Using linear regression, in UC there is an almost significant (P = 0.069) increasing trend with time but no difference by gender (P = 0.591). On the other hand, in CD there is no significant trend with time (P = 0.555) but almost a significant difference by gender (P = 0.078).

Conclusions: This is the first Maltese study in which the incidence of IBD has been recorded. In Malta the incidence of UC is similar to the overall incidence of other European countries while the incidence of CD is lower. In fact, the incidence rates of CD are among the lowest in Europe, similar to other southern European countries.
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April 2008