Objective Low molecular weight heparin (LMWH) is currently the most commonly used intravenous anticoagulant drugs, but the lack of point of care testing (POCT) limit its applications in patients with severe renal dysfunction and others. The purpose of this study was to explore the sensitivity of new activated clotting time (ACT) reagents for laboratory monitoring of LMWH.
Methods Blood samples collected from 30 healthy volunteers. After taking blood samples, different doses of low molecular weight heparin (dalteparin) were added and the anti-Xa level of final blood samples was 0.1–1.8 IU/ml. ACT and clot rate (CR) were measured with traditional reagent kaolin and new reagent magbar, Linear regression analysis was performed and a regression equation was established between different anti-factor Xa levels and the corresponding ACT, CR values.
Results With dalteparin concentration increased, the ACT values were gradually extended and the CR values were gradually reduced with both two reagents (kaolin and magbar). Analysis of dose-response curves obtained in vitro, an excellent linear relationship was observed between the ACT and dalteparin concentrations for all two reagents (p<0.01), and an exponential relationship was observed between the CR and dalteparin concentrations (p<0.01). Differences in slope of the regression curves of ACT were observed with the reagents tested (magbar 1097.6 s/IU vs kaolin 59.3 s/IU, p<0.01).
Conclusions This in vitro study has shown that the sensitivity of traditional ACT test reagent (kaolin) for laboratory monitoring of dalteparin was poor, and the sensitivity of new ACT test reagents (magbar) for laboratory monitoring of dalteparin increased significantly. The new reagents magbar may be used for bedside monitoring of anticoagulant activity of LMWH.
- Activated clotting time
- clot rate
- low molecular weight heparins