scope:

This guideline provides specifications for the one-stage clotting factor assay. It is intended to increase the diagnostic usefulness of the one-stage factor assay by providing the laboratory with necessary tools to minimize the effects of variables and to provide guidelines to enhance the precision and accuracy of patient results. Preexamination, examination, and postexamination issues specific to factor activity testing are covered.

This guideline is written for laboratory and/or diagnostic testing personnel responsible for factor assay testing including the performance, QC, and reporting of assays of coagulation factor activity, physicians (eg, hematologists, pathologists) responsible for interpreting results, external quality assessment (EQA) programs, and manufacturers of factor assay testing reagents and test systems.

This guideline does not cover chromogenic, two-stage clotting, antigenic, or manual methodologies for factor assays. Assays for fibrinogen, von Willebrand Factor (VWF), Factor XIII (FXIII), or contact factors of high molecular weight kininogen or prekallikrein are not covered in this guideline. Assays used to quantify inhibitors to specific factors are not covered in this guideline.