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Lab Manual for Moffitt-Long and Mount Zion

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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 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.
Normal range Negative
Synonyms Thrombosis risk mutations; Prothrombin 20210A; Hypercoagulability
Turn around times 7-10 days
Additional information An interpretation of this test by a laboratory physician will automatically be performed and billed for separately.

The Prothrombin G20210A mutation has a carrier frequency of 2.3% in Caucasians and results in overproduction of Prothrombin. Heterozygotes have a 3-4 fold increased risk of venous thrombosis. Although the risk in homozygotes has not been determined it is expected that such individuals will have a significantly elevated risk of thrombosis. Women heterozygous for the mutation and taking OCP have a 16-fold increased risk of VTE.

Double heterozygosity for FVL 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.
CPT coding 81240
LOINC code 24477-2
LDT or Mod FDA? Yes
Last Updated 1/22/2014 8:59:57 AM
Entry Number 1284

If you have additional questions regarding this test, please call: 415-353-1667

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