title: Pathology consultation on anticoagulation monitoring: factor X-related assays.
abstract: OBJECTIVE
  To review various anticoagulation therapies and related laboratory monitoring issues, with a focus on factor X-related chromogenic assays.
  
  
  METHODS
  A case-based approach is used to review pertinent published literatures and product inserts of anticoagulation drugs and to look back on clinical use of factor X-related chromogenic assays.
  
  
  RESULTS
  The number of anticoagulants available to clinicians has increased greatly in the past decade. Whether and how these anticoagulants should be monitored are areas of uncertainty for clinicians, which can lead to misuse of laboratory assays and suboptimal patient management. Factor X-related assays are of particular concern because of the similar and often confusing test names. Based on a common clinical case scenario and literature review regarding anticoagulant monitoring, an up-to-date discussion and review of the various factor X-related assays are provided, focusing on the differences in test designs and clinical utilities between the chromogenic anti-Xa and chromogenic factor X activity assays.
  
  
  CONCLUSIONS
  Anticoagulation therapy and related laboratory monitoring are rapidly evolving areas of clinical practices. A good knowledge of relevant laboratory assays and their clinical applications is necessary to help optimize patient care.
authors.affiliation: Laboratory Medicine Service, MC 113A, UCSF & VA Medical Center, 4150 Clement St, San Francisco, CA 94121; mark.lu@va.gov.
authors.forename: Geoffrey D
authors.initials: GD
authors.lastname: Wool
authors.forename: Chuanyi M
authors.initials: CM
authors.lastname: Lu
mesh_terms: D000284:Administration, Oral; D000925:Anticoagulants / Q000627:therapeutic use*; D001681:Biological Assay; D015415:Biomarkers / Q000097:blood; D001780:Blood Coagulation Tests; D016903:Drug Monitoring / Q000379:methods*; D062787:Drug Overdose / Q000517:prevention & control; D015951:Factor Xa / Q000378:metabolism*; D065427:Factor Xa Inhibitors; D006470:Hemorrhage / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D007262:Infusions, Intravenous; D007755:Laboratories, Hospital; D008297:Male; D008875:Middle Aged; D010340:Pathology, Surgical / Q000379:methods*; D012017:Referral and Consultation
chemical_list: D000925:Anticoagulants; D015415:Biomarkers; D065427:Factor Xa Inhibitors; D015951:Factor Xa
keywords: Anticoagulants; Anticoagulation monitoring; Chromogenic anti-Xa assay; Chromogenic factor X activity assay; Direct factor Xa inhibitor; Direct thrombin inhibitor; Factor X; Heparin; Warfarin