How I investigate for bleeding disorders

Introduction: Laboratory investigations for bleeding disorders are warranted when an individual has a personal and/or family history of bleeding, and/or laboratory findings that suggest the possibility of an inherited or acquired bleeding disorder. Methods: This review summarizes author's experience with ordering and reporting on diagnostic investigations for common and rare bleeding disorders, with consideration of recent articles on diagnosing bleeding disorders. An updated strategy is presented for investigating common and rare, congenital and acquired bleeding disorders. Results: An investigation of a suspected bleeding disorder requires a practical strategy that considers the clinical problem to be investigated, the pretest probability of true-positive and false-positive findings, the investigations can be performed locally or in a reference laboratory and limit the number of blood samples required to establish a diagnosis. It is often advantageous to simultaneously test for von Willebrand disease and platelet function disorders, and for coagulation defects, including fibrinogen disorders. An investigation for rarer bleeding disorders, including those affecting factor XIII, alpha(2) antiplasmin, and plasminogen activator inhibitor-1, is appropriate when faced with a severe congenital or acquired bleeding problem that cannot be explained by the initial diagnostic investigations. Conclusion: An organized strategy for investigating bleeding disorders that consider important issues, confirms abnormal findings, encourages proper interpretation of the results, and provides a helpful framework for assessing both common and rare causes of bleeding.