Test Details
Methodology
Polymerase chain reaction (PCR) with restriction enzyme digestion and polyacrylamide gel electrophoresis
Result Turnaround Time
3 - 9 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
This test provides information about additional risk for venous thrombosis among individuals known to be heterozygous for factor V Leiden (one copy of mutation). This knowledge aids in prevention of venous thrombosis. Factor V Leiden is the most common genetic risk factor for venous thrombosis and pulmonary embolism. It is present in 5% of the Caucasian population and in 20% to 40% of individuals with a history of venous thromboembolism. Not all individuals who are heterozygous for factor V Leiden will experience a thrombotic event, and the factor V R2 DNA analysis identifies some individuals at risk. Factor V Leiden heterozygotes are at a sevenfold increased risk for venous thrombosis compared to the general population. Coexistence of the R2 polymorphism with factor V Leiden increases that risk by an additional threefold, leading to an increased risk of approximately 16-fold.
Limitations
This is not a diagnostic test. It assesses increased risk of venous thromboembolism due to the presence of the factor V R2 variant in individuals who are heterozygous for factor V Leiden. Not all individuals with factor V R2 and factor V Leiden will have a venous thrombosis event in their lifetimes. Test results should be used in conjunction with clinical observation and other lab results.
Specimen Requirements
Specimen
Whole blood
Volume
5 mL
Minimum Volume
0.5 mL (Note: This volume does not allow for repeat testing.)
Container
Lavender-top (EDTA) tube (preferred) or yellow-top (ACD) tube
Storage Instructions
Maintain specimen at room temperature or refrigerate. Stable at room temperature and refrigerated for seven days.
Causes for Rejection
Clotted whole blood samples if adequate DNA not obtained; incorrect specimen type; frozen whole blood specimens
References
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 503940 | Factor V R2 DNA Analysis | 503942 | FV R2 DNA Analysis Result: | 41103-3 | ||
| 503940 | Factor V R2 DNA Analysis | 503941 | Methodology: | 49549-9 | ||
| 503940 | Factor V R2 DNA Analysis | 503944 | Interpretation: | 35474-6 | ||
| 503940 | Factor V R2 DNA Analysis | 503945 | Comment: | 77202-0 | ||
| Order Code | 503940 | |||||
| Order Code Name | Factor V R2 DNA Analysis | |||||
| Order Loinc | ||||||
| Result Code | 503942 | |||||
| Result Code Name | FV R2 DNA Analysis Result: | |||||
| UofM | ||||||
| Result LOINC | 41103-3 | |||||
| Order Code | 503940 | |||||
| Order Code Name | Factor V R2 DNA Analysis | |||||
| Order Loinc | ||||||
| Result Code | 503941 | |||||
| Result Code Name | Methodology: | |||||
| UofM | ||||||
| Result LOINC | 49549-9 | |||||
| Order Code | 503940 | |||||
| Order Code Name | Factor V R2 DNA Analysis | |||||
| Order Loinc | ||||||
| Result Code | 503944 | |||||
| Result Code Name | Interpretation: | |||||
| UofM | ||||||
| Result LOINC | 35474-6 | |||||
| Order Code | 503940 | |||||
| Order Code Name | Factor V R2 DNA Analysis | |||||
| Order Loinc | ||||||
| Result Code | 503945 | |||||
| Result Code Name | Comment: | |||||
| UofM | ||||||
| Result LOINC | 77202-0 |