With better outcomes from the anti-Xa assay (Paluri et al.
Therapeutic Ranges for aPTT and Anti-Xa Assay at UPMC Heparin Order Set Anti-Xa Therapeutic Ranges aPTT (seconds) (units/ML) DVT/PE 0.
Monitoring unfractionated heparin therapy: relationship between eight anti-Xa assays
and a protamine titration assay.
There were no sufficient data to compare the influence of bilirubin on anti-Xa assay
, because this analysis was not performed routinely in patients on ECMO, but from available data (n = 16) we noted that elevated free Hb 143 (99-198) mg/dL in plasma samples was accompanied with increased total bilirubin 10 (5-13) mg/dL; however, the correlation between these variables were poor (r =.
The lack of agreement between absolute clotting time values and heparin concentrations determined by anti-Xa assay
suggests the need for reexamination of the ECMO patient management strategy, perhaps in a multicenter pilot study using an evidence-based medicine approach.
However, a significant positive bias was observed with the anti-Xa assay
compared with the other methods.
Unfractionated heparin (UF) is commonly used in anticoagulant therapy and is monitored by a variety of methods including activated partial thromboplastin time (aPTT), anti-Xa assays
, and during surgery or other invasive procedures by the activated clotting time (ACT).