Factor V Leiden (FVL)
Department: Coagulation
Test Synonym(s): LAB346, FVL, APCR , FV Leiden, Activated Protein C Resistance
CPT Codes: 85307
Methodology: Clotting
Reference Range: Results >1.9 are normal. Heterozygotes for Factor V Leiden usually have results < 1.5. A result of 1.6 to 1.9 may be associated with heterozygosity for Factor V Leiden.
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 at -70C: 3 years
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: Twice per week
TAT: 1 - 3 days
Significance: Direct Thrombin and Direct and indirect Xa inhibitors may interfere with this assay.
Special Instructions: Deliver to lab immediately. Tubes must be filled to indicator line and not clotted. Indwelling lines should be flushed with saline only and 5 mL of blood should be discarded prior to collecting samples for coagulation studies. If sending plasma aliquots, DOUBLE CENTRIFUGE plasma samples to produce platelet poor plasma. Samples received from an outside lab must be aliquoted and frozen. Grossly hemlyzed, icteric or lipemic samples may be rejected. Ordering physician name and telephone contact information MUST accompany the sample and request. Vanderbilt Esoteric Coagulation Laboratory: 615 875-5633
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