Factor V Activity (F5)
Department: Coagulation
Test Synonym(s): LAB304, F5 Activity, F5
CPT Codes: 85220
Methodology: Clotting
Reference Range: 50 - 150%
Tube Type: One 2.7mL Light blue top - 3.2% Sodium Citrate
Specimen: Citrated platelet poor plasma - Requires double centrifugation if sending a plasma aliquot. Aliquot(s) must be frozen if not received by lab within 4 hours of collection.
Alternate Specimen: None
Pediatric Requirements: Pediatric: One 2.7mL Light blue top - 3.2% Sodium Citrate. Neonatal: One 1.8mL Light blue top - 3.2% Sodium Citrate.
Volume: 1.0 mL plasma
Minimum Volume: 1.0 mL plasma
Temperature: Room Temperature for Light blue top tube, must be received within 4 hours of draw. Plasma aliquot(s) must be frozen if not received by lab within 4 hours of collection.
Stability: Room temperature: 4 hours, Frozen: -70 C for one month
Reasons for Rejection: Clotted sample, incorrectly filled tubes, incorrect tube type, grossly hemolyzed sample, grossly lipemic sample, grossly icteric sample, whole blood >4.0 hours old
Days Performed: Monday - Friday
Times Performed: 8:00 AM - 3:00 PM Monday - Friday. 8:00 AM - 12:00 PM Saturday and Sunday. Tests requested after hours or on holidays have to be approved by the Medical Director.
TAT: 1 - 3 days
Significance: This test is not appropriate for ruling out Activated Protein C Resistance (Factor V-Leiden). The presence of a Lupus Anticoagulant in the sample may interfere with the assay. Direct Thrombin and both direct and indirect anti-Xa inhibitors may interfere with this assay.
Special Instructions: The Factor V Activity assay is not a test for Factor V Leiden (See Factor V Leiden [LAB346]). The test is not recommended for ruling out the presence of Factor V Leiden (Activated Protein C Resistance). Indwelling line should be flushed with saline and 5.0 mL of blood discarded before collecting samples for coagulation assays. Tube must be full and not clotted. Deliver to lab immediately. Samples received from an outside lab must be aliquoted and frozen. Samples aliquoted for shipping must be double centrifuged prior to freezing. Grossly hemolyzed, icteric or lipemic samples may be rejected.
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