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Factor V (F5) Leiden Mutation
|Utilization Guidelines||Tests with long turn-around times (ie. Molecular based tests and Microarrays) should only be requested on an inpatient if the result is going to affect the inpatient management.
If the patient will likely be discharged before the result will be available, the test should be requested after discharge. (NOTE: UCSF Medical Center is not reimbursed for inpatient testing).
An exception to the above may be appropriate if there is a possibility the patient will not survive to be discharged and the information is important for diagnosis and/or family decisions/management (ie. recurrence risk).
|Test group||Thrombosis risk|
|Performed by||Medical Genomics - Molecular Diagnostics|
|In House Availability||Run 2x per week, Tuesday & Thursday, day shift only|
|Method||PCR and allele-specific probes|
|Collection Instructions||If collecting in citrate, check the expiration date on the label of the blue top vacutainer before drawing the patient.
Do not collect sample in heparin. Keep sample refrigerated for overnight or longer storage.
For UCSF Samples (from remote sites) Click here for sample collection instructions
For NON-UCSF Samples Click here for Requisition form & Account set-up instructions. Note we only do institutional billing.
|Container type||Lavender top Blue (citrate) and Yellow (ACD) tops acceptable|
|Amount to Collect||3 mL blood (Note this volume is sufficient to perform all thrombosis risk factor mutations)|
|Sample type||Whole blood|
|Preferred volume||3 mL blood (Note this volume is sufficient to perform all thrombosis risk factor mutations)|
|Min. Volume||1.5 mL blood|
|UCSF Rejection Criteria||Heparinized (green top) samples.|
|Processing notes||Do not centrifuge the specimen. Store at room temperature. Refrigerated samples are acceptable.|
|Synonyms||Thrombosis risk mutations; Hypercoagulability; APC resistance; Activated protein C resistance; FV Q506; FVM; Factor V mutation|
|Turn around times||7-9 days|
|Additional information||An interpretation of this test by a laboratory physician will automatically be performed and billed for separately.
In patients with this mutation factor 5 is less susceptible to inactivation by Protein C. The R506Q mutation has a carrier frequency of 5% in Caucasians. Heterozygotes have a 7-fold increased risk of VTE and homozygotes have an 80-fold increased risk. Women heterozygous for the mutation and taking OCP have a 30-fold increased risk of VTE.
Double heterozygosity for the mutation and Prothrombin mutations confers a 20-fold increased risk of DVT.
If a mutation is detected it is recommended that the patient seek genetic counseling.
This test was developed and its performance characteristics determined by the Clinical Laboratories at the Medical Center at UC San Francisco. It has not been cleared or approved by the U.S. Food and Drug Administration.
|LDT or Mod FDA?||Yes|
|Last Updated||1/22/2014 8:59:56 AM|