Factor V (5) Leiden Gene Mutation

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Justification

The Factor V Leiden mutation causes resistance to activated protein C and is the most common inherited predisposition to venous thrombosis in Caucasian populations (40 to 50 percent of cases). Heterozygosity for the Factor V Leiden mutation confers an approximately sevenfold increased risk of thrombosis, while homozygosity for the mutation increases thrombosis risk 80-fold. It is present in 60% of thrombotic patients with normal levels of protein S, protein C, antithrombin, and antiphospholipid antibodies. The Factor V Leiden mutation has also been associated with spontaneous abortion and may be linked to recurrent pregnancy loss.

STAT: < 48 hours (M-F)

RT-PCR

Draw Tube: Purple Top

Sample Type: EDTA Whole Blood

DRAW KITS AVAILABLE

Specimen Requirements

	Sample Type	Volume Required	Minimum Volume	Stability
PREFERRED	EDTA Whole Blood	3mL	1mL	Room Temp.: 1 month Refrigerated: 1 month
ALTERNATIVE	Cheek swab	2 swab	-	Room Temp.: 1 month Refrigerated: 1 month

REJECTION CRITERIA	Sample contamination; sample compromised
SPECIAL INSTRUCTIONS	-

General Information

METHODOLOGY	RT-PCR
STAT TAT	< 48 hours (M-F)
STAT TAT Performance	> 90% of results released in 48 hours
ROUTINE TAT	< 3 days (M-F)
ALTERNATIVE NAMES	R506Q, G1691A, c.1601G>A, p.Arg534Gln, FVL
DESCRIPTION	This test detects the factor V Leiden variant (c.1601G>A, p.Arg534Gln) using real-time PCR. This test can detect whether a patient is normal or has one factor V Leiden allele (i.e., heterozygous) or two alleles (i.e., homozygous).
LIMITATIONS	Rare variants within the primer binding sites could lead to allele drop-out and a potential false negative result.
NORMAL RANGE	No mutation found
ASSOCIATED TESTING	-
REFERENCES	1. Van Cott EM, Khor B, Zehnder JL. Factor V Leiden. Am J Hematol. 2016 Jan;91(1):46-9. 2. Pritchard AM, Hendrix PW, Paidas MJ. Hereditary Thrombophilia and Recurrent Pregnancy Loss. Clin Obstet Gynecol. 2016 Sep;59(3):487-97.
SAMPLE REPORT	Upon request
NEW YORK STATE APPROVED	No

Test Codes

ORDER CODE	P3050
CPT CODE	81241
LOINC CODE	21667-1