Assays of procoagulant and anticoagulant factors in plasma are required to diagnose haemostatic abnormalities and to monitor treatment of replacement therapy. Well designed and controlled assays are important to ensure accurate and precise results are obtained. This guideline covers details of general assay design, including pre-analytical variables, reference ranges and cut-off values, and assay techniques and reagents. More specific detail is given for measurement of procoagulant clotting factors, and thrombophilia screening through assay of the natural anticoagulants antithrombin, protein C and protein S.

Declaration of Interests

The BSH paid the expenses incurred during the writing of this guidance. None of the authors had conflicts of interest to declare. All authors have made a declaration of interests to the BSH and Task Force Chairs which may be viewed on request.