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Methylenetetrahydrofolate Reductase mutations

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 MTR
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; MTHFR mutations; Hyperhomocysteinemia; Hypercoagulability; Methylene Tetrahydrofolate Reductase mutations
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 MTHFR mutation 677(C-T) has a carrier frequency of 35% in Caucasians and results in a thermolabile protein which decreases the availability of the N-methyltetrahydrofolate required in the remethylation reaction which controls plasma levels of homocysteine. Homozygosity results in mild hyperhomocysteinemia which is felt to be a risk factor for arterial and venous thrombosis. Risk parallels the level of homocysteine in the patient.

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 81291
LOINC code 38415-6
LDT or Mod FDA? Yes
Last Updated 1/22/2014 8:59:58 AM
Entry Number 1285
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