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HelpTest Code LAB3031 Factor V Leiden
Clinical System Name
Factor V Leiden Mutation - DNA
Synonyms
Factor 5 Leiden
Factor V Leiden
Factor V PCR
DNA-Factor V
Factor 5 DNA Screen
APC CoFactor-DNA
Description
The factor V Leiden variant (commonly known as R506Q, p.Arg506Gln, 1691G>A) in the factor V gene (F5) is present in approximately 3% of the general population, and in about 20-50% of patients with a history of unexplained recurrent venous thrombosis. The presence of a glutamine instead of an arginine residue removes a site in factor V that is normally cleaved by activated protein C, and is associated with resistance to activated protein C. Presence of this polymorphism substantially increases the lifetime risk of venous thrombosis. This test detects the underlying defect present in almost all cases of resistance to activated protein C.
Sample Requirements
Specimen: Whole Blood
Container(s): Lavender/EDTA or Yellow/ACD A or B
Preferred Vol: 3.0 mL (Adult), 2mL (child)
Minimum Vol: 1.0 mL
Specimen: DNA
Container(s): Sterile plastic tube
Preferred Vol: 20-30 ul of 100ng/ul concentration
Note: Only one sample is needed to perform both Factor V Leiden and Prothrombin Variant.
Alternative Specimen (e.g. salvia or buccal): Alternate Specimen Collection Kits for Genetic Testing
Processing Instructions
Reject due to: Dark Green/Sodium Heparin, Lt. Green/Lithium Heparin Microtainer
Spin: N
Aliquot: N
Temp: 2 - 4 C
Storage location: CPA 3 refrigerator, Send Outs rack.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood | Room Temp | 7 d |
| Refrigerated | 7 d | |
| Frozen | Unacceptable | |
| Extracted DNA | Room Temp | 3-4 d |
| Refrigerated | 1 y | |
| Frozen | Indefinitely |
Availability
| STAT | Performed | TAT |
|---|---|---|
| N | Weekly | 2 w |
Performing Laboratory
University of Washington
Department of Laboratory Medicine
UW Genetics Lab
1959 NE Pacific St, NW220
Seattle, WA 98195
Phone Number: (206) 520-4600
Department
Department: Send Outs/Genetic
Phone Number: (206) 987-2563
Reference Range
Normal result: no mutations detected.
Methodology
Method: Next-generation sequencing
Analysis of the F5 gene for the Leiden (p.R506Q) mutation.
The presence of either normal (Arg506/1691G) or mutant (Gln506/1691A; also known as Factor V Leiden) alleles of the F5 gene are detected by melting curve analysis of an amplified gene product. The Factor V Leiden variant is officially designated as NM_000130.4:c.1601G>A; NP_000121.2:p.Arg534Gln. This test was developed and its performance characteristics determined by the Department of Laboratory Medicine at the University of Washington.
Clinical Utility
Factor V Leiden Thrombophilia GeneReviews
The factor V Leiden mutation in the F5 gene is the most common cause of activated protein C (APC) resistance, and most common genetic risk factor for thrombosis. Approximately 3-8% of the population is heterozygous, and have an estimated 5-10 fold increased risk of thrombosis. Homozygotes have a 50-100 fold increased risk.
Send Out Instructions
| Reference Test Name: | Factor V DNA Screen |
| Reference Test Number: | F5DNA |
| Instructions: | Send out Monday through Friday with the UW courier. |
Exclude from UM database