Ordering Recommendations

This test is not recommended for nonsymptomatic patients under 18 years of age.

Performed

Monday - Friday

Methodology

Real-Time Polymerase Chain Reaction

Reported

Routine: 12 - 14 days

Synonyms

  • Factor 5 Leiden
  • F5 Leiden Mutation
  • 1691G>A
  • c.1601G>A
  • p.Arg534Gln
  • Human F5 Gene
  • F5 Mutation
  • Inherited Thrombophilia
  • Activated Protein C Resistance
  • APC Resistance
  • Clinical Genomics

Performing Lab

Clinical Genomics

Turnaround Time

14 days

Add-on Eligibility

Yes, within 7 days of collection
*If DNA has been extracted previously for other Clinical Genomics tests, this is stored for 6 weeks and may qualify for add-on

Specimen Type

Blood

Specimen Volume

5 mL (Minimum: 1 mL)

Collection Container

EDTA Whole Blood Tube (Lavender Top Vacutainer)

Unacceptable Conditions

  1. Severely clotted or grossly hemolyzed specimens
  2. Specimens that have been improperly collected, stored, or transported
  • Specimens collected in preservatives other than EDTA
    • ACD tubes are accepted, but EDTA is preferred
  • Serum or plasma
  • Specimens that have been frozen
  • Commingled specimens
  1. Specimens in tubes that have been damaged or broken during transport
  2. Specimens with insufficient volume for testing
  3. Unlabeled or mislabeled specimens

Storage/Transport Temperature

Transport Instructions      
Collection Location Transport Temperature Processing Required Timeframe
ED/Inpatient Room Temperature None Specimen must be received by the lab within 3 days of collection
Laboratory/Outpatient/Off-Site Room Temperature None Specimen must be received by the lab within 3 days of collection

Storage: Refrigerated

Stability (from collection to initiation)

Stability:
Prior to Extraction:
  • Room Temperature: 3 days
  • Refrigerated: 7 days
  • Frozen: Unacceptable
Extracted DNA:
  • Room Temperature: Unacceptable
  • Refrigerated: Unacceptable
  • Frozen: Indefinitely

Laboratory Storage: 
  • Original Specimen: Refrigerated
  • Extracted DNA: Frozen
Laboratory Retention: 
  • Original Specimen: 6 weeks
  • Extracted DNA: 6 weeks

Collection Instructions

Labeling Instructions:
When labeling blood tubes, leave a small window visible for the lab to assess the fill volume and sample integrity. Ensure that the barcode is in the correct orientation.


Collection Instructions:
Follow the correct order of draw when collecting with additional orders and tube types:
     

Reference Interval

Not Detected: Negative for the factor V Leiden, R506Q mutation

Interpretive Data

Factor V Leiden mutation is the most common cause of inherited thrombophilia and accounts for over 90% of activated protein C resistance. Inherited thrombophilia predisposes an individual to thrombotic events such as venous thrombosis, a common cardiovascular disease. APC resistance is the most prevalent coagulation abnormality associated with venous thrombosis. Heterozygosity for the F5 c.1601G>A variant is found in 1% to 7% of the general population depending on ethnicity, 15% to 20% of individuals with a first venous thromboembolism (VTE), and up to 50% of individuals with recurrent VTE or estrogen related thrombosis.

Lifetime risks of venous thromboembolisms are higher when environmental risk factors such as obesity and smoking are also present.

Incidence:
Heterozygosity occurs in:
  • Caucasians: 5%
  • Hispanics: 2%
  • African Americans: 1%
  • Asians: 0.5%
Homozygosity occurs in 1 in 5,000 individuals

Inheritance: Autosomal dominant with reduced penetrance

Penetrance: Lifetime risk of venous thromboembolism is 10% for heterozygotes and almost 100% for homozygotes

Cause: A deleterious F5 gene mutation R506Q (1691G>A)
* NOTE: Standardized nomenclature for the Factor V Leiden mutation is c.1601G>A (p.Arg534Gln)

Clinical Sensitivity and Specificity: 99%

Methodology: Polymerase chain reaction and fluorescence monitoring

Analytical Sensitivity and Specificity: 99%

Limitations: This test is specific for the F5 c.1601G>A variant and will not detect other variants within the F5 gene or within other genes. Diagnostic error may occur with this test due to rare genetic variation at a primer binding site.

This test was developed and its performance characteristics determined by the UC San Diego Health System Molecular Diagnostics Laboratory. It has not been cleared or approved by the US Food and Drug Administration. FDA clearance or approval is not required for clinical use. The result of this test should be interpreted using all relevant clinical data and should not be used alone for clinical diagnosis or patient management decisions.
Ordering

Ordering Recommendations

This test is not recommended for nonsymptomatic patients under 18 years of age.

Performed

Monday - Friday

Methodology

Real-Time Polymerase Chain Reaction

Reported

Routine: 12 - 14 days

Synonyms

  • Factor 5 Leiden
  • F5 Leiden Mutation
  • 1691G>A
  • c.1601G>A
  • p.Arg534Gln
  • Human F5 Gene
  • F5 Mutation
  • Inherited Thrombophilia
  • Activated Protein C Resistance
  • APC Resistance
  • Clinical Genomics

Performing Lab

Clinical Genomics

Turnaround Time

14 days

Add-on Eligibility

Yes, within 7 days of collection
*If DNA has been extracted previously for other Clinical Genomics tests, this is stored for 6 weeks and may qualify for add-on
Collection

Specimen Type

Blood

Specimen Volume

5 mL (Minimum: 1 mL)

Collection Container

EDTA Whole Blood Tube (Lavender Top Vacutainer)

Unacceptable Conditions

  1. Severely clotted or grossly hemolyzed specimens
  2. Specimens that have been improperly collected, stored, or transported
  • Specimens collected in preservatives other than EDTA
    • ACD tubes are accepted, but EDTA is preferred
  • Serum or plasma
  • Specimens that have been frozen
  • Commingled specimens
  1. Specimens in tubes that have been damaged or broken during transport
  2. Specimens with insufficient volume for testing
  3. Unlabeled or mislabeled specimens

Storage/Transport Temperature

Transport Instructions      
Collection Location Transport Temperature Processing Required Timeframe
ED/Inpatient Room Temperature None Specimen must be received by the lab within 3 days of collection
Laboratory/Outpatient/Off-Site Room Temperature None Specimen must be received by the lab within 3 days of collection

Storage: Refrigerated

Stability (from collection to initiation)

Stability:
Prior to Extraction:
  • Room Temperature: 3 days
  • Refrigerated: 7 days
  • Frozen: Unacceptable
Extracted DNA:
  • Room Temperature: Unacceptable
  • Refrigerated: Unacceptable
  • Frozen: Indefinitely

Laboratory Storage: 
  • Original Specimen: Refrigerated
  • Extracted DNA: Frozen
Laboratory Retention: 
  • Original Specimen: 6 weeks
  • Extracted DNA: 6 weeks

Collection Instructions

Labeling Instructions:
When labeling blood tubes, leave a small window visible for the lab to assess the fill volume and sample integrity. Ensure that the barcode is in the correct orientation.


Collection Instructions:
Follow the correct order of draw when collecting with additional orders and tube types:
     
Result Interpretation

Reference Interval

Not Detected: Negative for the factor V Leiden, R506Q mutation

Interpretive Data

Factor V Leiden mutation is the most common cause of inherited thrombophilia and accounts for over 90% of activated protein C resistance. Inherited thrombophilia predisposes an individual to thrombotic events such as venous thrombosis, a common cardiovascular disease. APC resistance is the most prevalent coagulation abnormality associated with venous thrombosis. Heterozygosity for the F5 c.1601G>A variant is found in 1% to 7% of the general population depending on ethnicity, 15% to 20% of individuals with a first venous thromboembolism (VTE), and up to 50% of individuals with recurrent VTE or estrogen related thrombosis.

Lifetime risks of venous thromboembolisms are higher when environmental risk factors such as obesity and smoking are also present.

Incidence:
Heterozygosity occurs in:
  • Caucasians: 5%
  • Hispanics: 2%
  • African Americans: 1%
  • Asians: 0.5%
Homozygosity occurs in 1 in 5,000 individuals

Inheritance: Autosomal dominant with reduced penetrance

Penetrance: Lifetime risk of venous thromboembolism is 10% for heterozygotes and almost 100% for homozygotes

Cause: A deleterious F5 gene mutation R506Q (1691G>A)
* NOTE: Standardized nomenclature for the Factor V Leiden mutation is c.1601G>A (p.Arg534Gln)

Clinical Sensitivity and Specificity: 99%

Methodology: Polymerase chain reaction and fluorescence monitoring

Analytical Sensitivity and Specificity: 99%

Limitations: This test is specific for the F5 c.1601G>A variant and will not detect other variants within the F5 gene or within other genes. Diagnostic error may occur with this test due to rare genetic variation at a primer binding site.

This test was developed and its performance characteristics determined by the UC San Diego Health System Molecular Diagnostics Laboratory. It has not been cleared or approved by the US Food and Drug Administration. FDA clearance or approval is not required for clinical use. The result of this test should be interpreted using all relevant clinical data and should not be used alone for clinical diagnosis or patient management decisions.

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