A multicenter study on amidolytic factor X evaluation in oral anticoagulant therapy

Area of Science:

• Clinical Chemistry
• Hematology
• Laboratory Medicine

Background:

• Oral anticoagulation therapy requires regular laboratory monitoring.
• Prothrombin time (PT) assays face standardization challenges.
• Amidolytic factor X (F X) determination is proposed as a potential alternative.

Purpose of the Study:

• To validate the amidolytic F X assay for large-scale laboratory control of oral anticoagulation.
• To assess the reproducibility and correlation of F X assay with PT.
• To evaluate the suitability of F X assay for long-term anticoagulation monitoring.

Main Methods:

• A multicenter study involving 6 French laboratories.
• Use of a single chromogenic substrate (Stachrom X Stago) across different automated instruments.
• Estimation of intra- and inter-laboratory reproducibility of F X on fresh and lyophilized patient plasmas.
• Comparison of F X assay results with PT in over 500 patients on stabilized oral anticoagulant treatment.

Main Results:

• High intra- and inter-laboratory reproducibility for F X determination was observed.
• Strong positive correlation between F X assay and PT results in all participating centers.
• Standardization of the F X method appeared independent of the chromogenic substrate used.
• Concordant information between PT and F X assay was found in 76% of patients.

Conclusions:

• Amidolytic F X determination demonstrates satisfactory reproducibility and correlation with PT.
• The assay shows potential as a suitable method for monitoring long-term oral anticoagulation.
• Prospective trials are recommended to compare its clinical usefulness against conventional methods.