Objectives: To review the state of the art relating to elevated hemostatic factor levels as a potential risk factor for thrombosis, as reflected by the medical literature and the consensus opinion of recognized experts in the field, and to make recommendations for the use of specific measurements of hemostatic factor levels in the assessment of thrombotic risk in individual patients.
Data sources: Review of the medical literature, primarily from the last 10 years.
Data extraction and synthesis: After an initial assessment of the literature, key points were identified. Experts were assigned to do an in-depth review of the literature and to prepare a summary of their findings and recommendations. A draft manuscript was prepared and circulated to every participant in the College of American Pathologists Conference XXXVI: Diagnostic Issues in Thrombophilia prior to the conference. Each of the key points and associated recommendations was then presented for discussion at the conference. Recommendations were accepted if a consensus of the 27 experts attending the conference was reached. The results of the discussion were used to revise the manuscript into its final form.
Conclusions: Consensus was reached on 8 recommendations concerning the use of hemostatic factor levels in the assessment of thrombotic risk in individual patients. Detailed discussion of the rationale for each of these recommendations is presented in the article. This is an evolving area of research. While routine use of factor level measurements is not recommended, improvements in assay methodology and further clinical studies may change these recommendations in the future.