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Test Code FV LEIDEN Factor V Leiden

Clinical System Name

Factor V Leiden Mutation - DNA


Factor 5 Leiden


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.


This test is indicated for:

  • Individuals with family history of the factor V Leiden mutation
  • Individuals with a history of venous thromboembolism (VTE), as part of thrombophilia work up

Sample Requirements

Specimen: Whole blood

Container(s): Lavender/EDTA, Yellow/ACD A or B, or Lt. Blue Top/Citrate
Preferred Vol: 3 mL

Minimum Vol: 2 mL

Only one sample is needed to perform both Factor V Leiden and Prothrombin Variant.


Specimen: Buccal Swab

Container(s): Buccal Swab

Preferred Vol: 4-6 swabs

Minimum Vol: 2 swabs

Note:  For swabs, call Send Outs (M-F, 8-5), 987-2563


Specimen: Cells

Container(s): Lt. Blue/Citrate

Preferred Vol: 3 mL

Minimum Vol: 1 mL

Note:  Cells separated from plasma.

Processing Instructions

Reject due to: Heparin

Spin: No

Aliquot: No

Temp: Refrigerate

Storage location: CPA refrigerator sendouts rack


Specimen Type Temperature Time
Whole blood Room temp 3 days
Whole blood Refrigerated 7 days
Buccal swab Refrigerated 1 day



STAT Performed TAT
Contact lab Weekly 1 - 2 w


Performing Laboratory

University of Washington

Dept of Laboratory Medicine

UW Genetics Lab
1959 NE Pacific St, NW220
Seattle, WA 98195

Phone Number: (206) 520-4600


Department: Send Outs
Phone Number: (206) 987-2563

Reference Range

Interpretive report will be provided


Method: PCR

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.

Special Instructions





Clinical Utility

 Factor V Leiden Thrombophilia Gene Review

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.


Note that this test can be ordered individually or as part of a thrombosis risk panel that includes the prothrombin 20210G>A mutation in the F2 gene.

Send Out Instructions


Reference Test Name: Factor V DNA Screen
Reference Test Number: F5DNA
Instructions: Send out M - F with the UW courier.