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Ups J Med Sci. 2017 Aug;122(3):171-176. doi: 10.1080/03009734.2017.1370040. Epub 2017 Sep 11.

A novel prothrombin time method to measure all non-vitamin K-dependent oral anticoagulants (NOACs).

Author information

1
a Department of Clinical Chemistry , Linköping University , Linköping , Sweden.
2
b Department of Clinical and Experimental Medicine , Linköping University , Linköping , Sweden.
3
c Department of Acute Internal Medicine , Linköping University , Linköping , Sweden.
4
d Department of Medical and Health Sciences , Linköping University , Linköping , Sweden.
5
e Zafena AB , Borensberg , Sweden.

Abstract

BACKGROUND:

There is a clinical need for point-of-care (POC) methods for non-vitamin K-dependent oral anticoagulants (NOACs). We modified a routine POC procedure: Zafena's Simple Simon™ PT-INR, a room-temperature, wet-chemistry prothrombin time method of the Owren-type.

METHODS:

To either increase or decrease NOAC interference, two assay variants were devised by replacing the standard 10 µL end-to-end capillary used to add the citrated plasma sample to 200 µL of prothrombin time (PT) reagent by either a 20 µL or a 5 µL capillary. All assay variants were calibrated to show correct PT results in plasma samples from healthy and warfarin-treated persons.

RESULTS:

For plasmas spiked with dabigatran, apixaban, or rivaroxaban, the 20 µL variant showed markedly higher PT results than the 5 µL. The effects were even more pronounced at room temperature than at +37 °C. In plasmas from patients treated with NOACs (n = 30 for each) there was a strong correlation between the PT results and the concentration of NOACs as determined by the central hospital laboratory. For the 20 µL variant the PT response of linear correlation coefficient averaged 0.90. The PT range was INR 1.1-2.1 for dabigatran and apixaban, and INR 1.1-5.0 for rivaroxaban. Using an INR ratio between the 20 µL and 5 µL variants (PTr20/5) made the NOAC assay more robust and independent of the patient sample INR value in the absence of NOAC. Detection limits were 80 µg/L for apixaban, 60 µg/L for dabigatran, and 20 µg/L for rivaroxaban.

CONCLUSIONS:

A wet-chemistry POC PT procedure was modified to measure the concentrations of three NOACs using a single reagent.

KEYWORDS:

Anticoagulant; apixaban; dabigatran; prothrombin time; rivaroxaban

PMID:
28891412
PMCID:
PMC5649322
DOI:
10.1080/03009734.2017.1370040
[Indexed for MEDLINE]
Free PMC Article

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