ANTI XA ASSAYS FOR DANAPAROID: ASSESSMENT OF PRE ANALYTICAL AND ANALYTICAL VARIABLES
Abstract number: P-T-682
Wemyss1 A., Smith1 J.M., Woolley2 A., Storr1 J., Maclean3 R., Hampton3 E., Kitchen3 S.
11Coagulation Dept, Northern General Hospital 22Coagulation Dept, Royal Hallamshire Hospital 33Coagulation Dept, Sheffield Teaching Hospitals, Sheffield, United Kingdom
How-to-cite Wemyss A, Smith JM, Woolley A, Storr J, Maclean R, Hampton E, Kitchen S. ANTI XA ASSAYS FOR DANAPAROID: ASSESSMENT OF PRE ANALYTICAL AND ANALYTICAL VARIABLES. J Thromb Haemost 2007; 5 Supplement 2: P-T-682
Introduction: Danaparoid sodium (Orgaran®, Organon Ltd.) is used for the treatment of some patients with heparin induced thrombocytopaenia and monitoring is useful in some cases. The test of choice for monitoring therapy is chromogenic anti Xa assay. We studied the stability of anti Xa activity in samples from patients undergoing danaparoid therapy and also assessed a number of analytical variables.
Methods: All assays were performed using Coamatic Heparin (anti Xa) assay (Chromogenix Ltd.). Stability of anti Xa activity in danaparoid treated patients was assessed in both platelet poor plasma (n=7) and in plasma separated from whole blood (n=5) following storage at room temperature (RT) for 2, 4, 8, 24 and 48 hr. Analytical performance was assessed using 5 samples prepared by in vitro addition of danaparoid to plasma. Comparisons were made using a series of calibration curves varying: danaparoid preparation (n=3), source of pooled normal plasma (PNP) (n=4), and Sysmex CA series instrument (n=3).
Results: There was no significant loss of anti Xa activity within a 48 hour period of storage at room temperature, in plasma stored as whole blood prior to separation (range of mean values 0.31 0.32 u/ml at different time points) or platelet poor plasma (means all 0.30 u/ml). There was no significant difference between results obtained with different instruments. The mean results of test samples assayed against calibration curves obtained from different danaparoid preparations (same PNP) were 0.50-0.58 u/ml (p<0.0001) and against curves obtained from different PNP source (same danaparoid) 0.57- 0.61 u/ml (p<0.0001). The inter assay precision of a QC sample was 3.3% (n=10, mean=0.53 u/ml).
Conclusions: We conclude that anti Xa activity of danaparoid is stable in plasma, or plasma separated from stored whole blood for at least 48hr at RT. Only minor effects were observed in assayed anti Xa values calculated from calibration curves prepared using different sources of PNP or danaparoid lots.
To cite this abstract use the following format:
Journal of Thrombosis and Haemostasis 2007; Volume 5, Supplement 2: abstract number
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