Hemostasis Reference Laboratory

Factor V Activity

• Transaction Code: 3210-11
• CPT Code (Suggested): 85220

A one-stage extrinsic system clotting assay is used to measure the factor V level. Clotting times of dilutions of patient plasma are compared to dilutions of a plasma pool from normal donors, when added to deficient plasma. Levels are reduced by hereditary or acquired factor V deficiency, factor V inhibitor (including those seen after use of topical bovine thrombin), liver disease, or disseminated intravascular coagulation (DIC). The factor V (Leiden) mutation associated with activated protein C resistance does not affect factor V activity and is tested by separate kinetic or DNA testing (described later).

• Sample Required: 0.5 ml frozen plasma x4 or (2) 3.2% sodium citrated tubes, 5 ml each.
• See Sample Requirements when ordered with other tests.
• Normal Range: 78-131% effective 11/1/11
• Analytic Time: Performed weekly, available STAT