Factor V

Factor V Leiden

Test Code
Factor V Leiden (FV)

CPT Code
81241 

Specimen
Whole blood or buccal swabs 

Volume
5 mL of whole blood or four buccal swabs

Minimum Volume
3 mL of whole blood or four buccal swabs 

Container
Lavender-stopper (EDTA) tube or paper envelope for dried buccal swabs 

Storage Instructions
Maintain at room temperature or refrigerate 

Cause for Rejection
Hemolyzed specimen; quantity not sufficient

General Purpose and Use
The Factor V Leiden polymorphism is the result of a single point mutation (1691 G>A) that results in substitution of a glutamine for arginine at amino acid 506. The amino acid change prohibits the inactivation of Factor V by activated protein C, thereby creating a state of activated protein C resistance (APCR) and increasing the risk of thrombosis. Individuals with this polymorphism have a 10-20 fold increased thrombotic risk.

Alleles Detected:
1691G>A

Limitations
Other genetic variants of the Factor V gene that are not detected in the assay may influence Factor V activity.  Other genetic and non-genetic factors may also influence the balance of proper coagulation. 

Methodology
Real-time polymerase chain reaction with fluorescence detection.

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