Abstract Number: PB0063
Meeting: ISTH 2021 Congress
Background: Unfractionated heparin (UFH) and low molecular weight heparin (LMWH) are the main injectable anticoagulant. The monitoring by anti-Xa activity is mainly used for UFH and occasionally for LMWH but data on stability before analysis remains limited. According to medical societies anti-Xa activity should be done within 2h for UFH and 6h for LMWH. However, discrepancies exist depending on the reagents used and the type of tubes.
Aims: The aim of this study is to determine the stability of anti-Xa UFH and LMWH activities on Stago and Siemens analyzers, with citrated tubes with and without theophylline, adenosine dipyridamole (CTAD).
Methods: The first 14 patients from the Clermont-Ferrand University hospital anticoagulated with UFH or LMWH, whose blood was drawn on citrated tubes or CTAD were included (total of 56 patients). The samples were centrifuged at 2200g for 15 min within an hour (T1) and the anti-Xa activity was determined immediately then 4h and 6h(T6) after the blood sample. Anti-Xa activities were determined on StaR with STALiquid anti-Xa reagent (Stago) and on CS2100 with Innovance Heparin reagent (Siemens). Results (U/mL) are expressed as the median (min-max).
Results: UFH anticoagulated patients show stable anti-Xa activities for up to 6h after collection on CTAD tube. Anti-Xa activities on citrated tube are significantly reduced at 6h with respectively 0.25(T1) (0.12-0.63) and 0.20 (0.10-0.55) (p<0.01) for Stago and 0.28 (T1) (0.18-0.50) and 0.26 (0.16-0.47) (p<0.001) for Siemens (Figure 1).
Patients anticoagulated with LMWH show stable anti-Xa activities for up to 6h. Anti-Xa activities on CTAD tube are stable at 6h for Stago and 4h for Siemens. Anti-Xa activities are increased at 6h for Siemens with respectively 0.20 (T1) (0.11-1.22) and 0.22 (0.11-1.25) (p<0.05) (Figure 2).
Conclusions: Anti-Xa UFH activity on citrated tube is reduced at 6h without clinical impact whatever the reagent.
To cite this abstract in AMA style:Sinegre T, Gremillet M, Fourneyron V, Tillier M, Trayaud A, Talon L, Lebreton A. Monitoring Heparin: Stability of Two Different Anti-Xa Assays in Citrated vs CTAD Tubes [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/monitoring-heparin-stability-of-two-different-anti-xa-assays-in-citrated-vs-ctad-tubes/. Accessed November 29, 2023.
« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/monitoring-heparin-stability-of-two-different-anti-xa-assays-in-citrated-vs-ctad-tubes/