Determination of dabigatran in plasma, serum, and urine samples: comparison of six methods

Abstract

Background: Assessing the anticoagulant effect of dabigatran may be useful in certain clinical settings. When plasma sampling is not available, serum or urine samples may provide another option for dabigatran determinations. Methods: Dabigatran was assessed in patients on treatment under real-life conditions in plasma samples by four clotting time-based assays and in plasma, serum, and urine samples by two chromogenic substrate methods. Results: The concentrations of dabigatran in patients' plasma samples were not different for the Hemoclot test (106.8 ± 89.4 ng/mL) and the ecarin clotting time (ECT, 109.5 ± 74.5 ng/mL, p = 0.58). Activated partial thromboplastin time and prothrombinase-induced clotting time showed low correlations with the other assays. Chromogenic assays measured similar concentrations as Hemoclot and ECT. For both chromogenic assays, the concentrations of dabigatran were about 70% lower in serum than in plasma samples (p < 0.0001). The intra-class coefficient (ICC, Bland-Altman analysis) was strong comparing ECT, Hemoclot thrombin inhibitor (HTI) assay, and the two chromogenic assays (r = 0.889-0.737). The ICC was low for comparisons of the chromogenic assays of serum vs. plasma values (ICC, 0.15 and 0.66). The ICC for the determination of

Measurement of dabigatran, rivaroxaban and apixaban in samples of plasma, serum and urine, under real life conditions. An international study

“…The confirmatory results also refer to serum and urine samples and to the POCT test in urine samples; they corroborate the reported limitation for serum samples from patients treated with dabigatran [25]. Separate standardisations of methods will be required for all matrices and all assays.…”

“…Then, 100 μL of 0.74 NIH/mL human thrombin (Sigma Aldrich, Deisenhofen, Germany) were added followed by incubation for 60 s. Fifty μL chromogenic substrate S2238 (1.59 mmol/L, Chromogenix, Essen, Germany) dissolved in distilled water were added and incubated for 5 min at 37 °C. The reaction was stopped by adding 25 μL of 20% acetic acid (LOD 21 ng/mL) [25]. All samples were analysed in duplicates.…”

“…5 μL test or calibration samples were mixed as duplicates with 25 μL DTI substrate reagent and then 50 μL of the thrombin reagent were added in 96-well microtitre plate to start the reaction. The reaction was stopped by adding 10 μL 20% acetic acid and measured as described (LOD 227 ng/mL) [25].…”

The laboratory's 2015 perspective on direct oral anticoagulant testing

“…Other methods for quantifying or estimating drug concentrations have been described for use in patients with a known history of DOAC use, including dilute Russell's viper venom time (DRVVT) , modified PT , point‐of‐care methods , chromogenic anti‐FXa , thrombin generation assays , and thromboelastometry , but all lack specificity for DOACs, which limits their use as a screening or quantifying method. Urinary methods for measuring the metabolites of dabigatran or rivaroxaban offer interesting alternatives to blood testing, but these methods do not correlate with the concentration of drug in the blood, and their results should be interpreted with caution . Laboratory and clinician interpretation of data must incorporate clinical history and presentation to assess coincidental findings (e.g.…”

Measurement and reversal of the direct oral anticoagulants

“…38 Urine-based assays may be useful for identifying whether the patient has taken dabigatran recently when history is not available, but correlate poorly with plasma drug levels. 39 A chromogenic anti-IIa assay is also under investigation and appears to correlate with HPLC-MS/MS (r 2 0.81) but data are limited and the assay is not widely available. 40 …”