Comparison of a Novel Fluorogenic Anti-FXa Assay with a Central Laboratory Chromogenic Anti-FXa Assay for Measuring LMWH Activity in Patient Plasmas
Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence
1.6 BIOLOGICAL SCIENCES
Introduction: Low molecular weight heparins (LMWHs) are used worldwide for the treatment and prophylaxis of thromboembolic disorders. Routine laboratory tests are not required due to the predictable pharmacokinetics of LMWHs, with the exception of pregnant patients, children, patients with renal failure, morbid obesity, or advanced age. Anti-Factor Xa (anti-FXa) plasma levels are most often employed in the assessment and guidance of accurate dosing in these patient cohorts. Materials and methods: A LMWH calibration curve was generated using citrated human pooled plasma spiked with pharmacologically relevant concentrations (0–1 U/ml) of two low molecular weight heparins; enoxaparin and tinzaparin. Least squares analysis determined the best curve fit for this set of data which returned low sum of squares (SS) values for the log linear fit with an R2 value of 0.995. Patient sample concentrations for the fluorogenic anti- FXa assay were determined using the log linear regression equation and correlated with the values reported by the hospital’s standard chromogenic assay. Results: A statistically significant correlation was found between the fluorogenic and the chromogenic anti-FXa assays for 10 patient samples, with a slope of 0.936, offset of 0.228 and an R2 of 0.71 (p
Harris, L., Castro-Lopez, V., O'Donnell, J. S. and Killard, A. (2011) Comparison of a novel fluorogenic anti-FXa assay with a central laboratory chromogenic anti-FXa assay for measuring LMWH activity in patient plasmas. Thrombosis Research 2011 Dec;128(6):e125-9. doi:10.1016/j.thromres.2011.07.011
Thrombosis Research 2011 Dec;128(6):e125-9.