PB0097 - Performance evaluation of a new anti-Xa assay which utilizes hybrid calibration curve for the monitoring of unfractionated and low molecular weight heparin

Background: Monitoring of heparin is important to adjust the heparin dose and manage anticoagulation therapy appropriately. Recently, new applications for the measurement of heparin and DOACs (Rivaroxaban, Apixaban and Edoxaban) were developed. The heparin assay permits the measurement of both unfractionated heparin (UFH) and low molecular weight heparin (LMWH) by utilizing a single hybrid calibration curve.

Aims: To evaluate the performance of the newly developed heparin assay with hybrid calibration.

Methods: Analytical performances were evaluated including measurement range, precision and trueness. Method comparison with a reference device was performed on patients under heparin therapy: 100 UFH and 100 LMWH citrated plasmas from a private laboratory. All measurements were performed on a fully automated coagulation analyzer.

Results: Linearity and limit of quantitation studies demonstrated a measuring range from 0.05 to 1.74 IU/mL. Repeatability results demonstrated that coefficient of variation (CV%) are less than 3%. Within-laboratory precision study results demonstrated that CV% are less than 4%. Trueness study results demonstrated that bias are less than 9%. Reagent is stable for 3 months at 2-8°C after opening or 7 days onboard. An excellent correlation with the reference device was obtained in method comparison study with a correlation coefficient at 0.991 (y = 0.99x + 0.10).

Conclusion(s): This new anti-Xa assay with hybrid calibration is a fully automatable, simple, standardized and highly sensitive assay, to rapidly assess Heparin concentrations in human citrated plasma. With low CVs, long stability, this assay is safe and accurate for monitoring patients on heparin therapy (UFH/LMWH).