The new trend in laboratory assay of NOACs

New Oral Anti-Coagulants (NOACs) are becoming more and more popular now and overwhelming majority of patients are taking NOACs as thrombo-prophylaxis now. The merits of NOACs include wide therapeutic index and stable pharmacokinetics and hence there's no need for laboratory monitoring. However, there are some clinical circumstances that laboratory observance of NOACs is essential for patient’s care; for instance, patients undergoing invasive procedures or patients affected by bleeding complications. Various principles of laboratory assay are available for measuring the drug level of dabigatran, rivaroxaban and apixaban. The measurement of rivaroxaban and apixaban are often done by anti-Xa assay and dilute thrombin time are often used to measure the extent of dabigatran. Some review articles mentioned that the worth of specific assay of NOACs is uncertain, mainly because the precision and accuracy of the precise assay isn't optimal, especially for low drug level. Nowadays, some companies provide kit with low-level calibrator so enhance precision of measurement of low drug level. In our  research, we use the diluted thrombin time kits and anti-Xa kits from Werfen and Sysmex Company for assessing and estimating the drug assay of dabigatran and rivaroxaban. The precision, accuracy, linearity and limit of detection are acceptable for computing various levels of dabigatran and rivaroxaban, including low drug concentrations and therefore the performance of the kits provided by two companies are comparable. The relationship between the drug levels of NOACs with regime coagulation screening tests was also assessed. The issue of internal control and a few practical issues for implementation of the precise laboratory assay of NOACs also will be discussed.

Author(s): Sin Chun Fung

Abstract | PDF

Share This Article