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Prothrombin (20210) mutation

Item Value
Approval req'd? No
Available Stat? No
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 code PTTR
Test group Thrombosis risk
Performed by Medical Genomics - Molecular Diagnostics
In House Availability Run once per week, or as needed, day shift only
Method PCR and allele-specific probes
Collection Instructions Do not collect sample in heparin. Keep sample refrigerated for overnight or longer storage.
Container type Lavender top preferred, Blue top 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 Inadequate sample. Samples collected in heparin.
Processing notes Do not centrifuge the specimen. Store at room temperature. Refrigerated samples are acceptable.
Normal range Negative
Synonyms Thrombosis risk mutations; Prothrombin 20210A; Hypercoagulability
Turn around times 7-10 days
Additional information Mutation and Incidence
The Prothrombin 20210G>A mutation (NM_000506.4(F2):c.*97G>A) is located in the 3' untranslated region of this gene. It has an estimated prevalence of 2% in Caucasians and is rare among Asians or Africans.

Pathogenicity
The Prothrombin 20210G>A mutation results in increased levels of plasma prothrombin and a concurrent increased risk of thrombosis. The mutation alters the polyadenylation site of the gene and results in increased mRNA synthesis and a subsequent increase in protein expression.

Thrombosis Risk
Heterozygosity for the Prothrombin 20210G>A carries a 3-4 fold increased risk of venous thromboembolism (VTE).
Women heterozygous for this mutation and taking oral contraceptive pills have an approximately 16-fold increased risk of VTE.

Homozygosity for F2 20210G>A is expected to significantly elevate the risk of thrombosis, however, its precise risk has not been determined.

An interpretation of this test by a laboratory physician will automatically be performed and billed for separately.

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.
CPT coding 81240
LOINC code 24477-2
LDT or Mod FDA? Yes
Last Updated 7/19/2017 9:51:27 PM
Entry Number 1284
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