Lab Dept:


Test Name:

Prothrombin 20210A Mutation

General Information

Lab Order Codes:



PT Mutation; Factor 2 by Invader; Factor 2 Mutation; Prothrombin 20210A Genetic Mutation; PTNT

CPT Codes:

81240 – F2, gene analysis, 20210G>variant

Test Includes:

Prothrombin 20210A Mutation


Test Indications:

Direct mutation analysis for the Pt G20210A allele should be reserved for patients with clinically suspected thrombophilia.

There may be additional indications for direct Pt G20210A mutation testing, such as in determining the duration of anticoagulant therapy of venous thromboembolism patients and screening for women contemplating oral contraceptive use or pregnancy. These testing and management strategies require formal evaluation before general implementation.

Lab Testing Section:

Coagulation - Sendouts

Referred to:

Mayo Medical Laboratories (Test# PTNT/81742)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

3 – 4 days, test set up Monday – Friday.

Special Instructions:

A Mayo Connect or Mayo Coagulation Request Form must accompany the specimen to the reference lab for processing. Mayo will not process the specimen without the appropriate information. Children’s laboratory has forms available.


Specimen Type:

Whole blood


Yellow top (ACD) (Solution A or B) tube
Alternate: Lavender top (EDTA) tube, Blue top (Na Citrate) tubes

Draw Volume:

3 mL (Minimum: 1 mL) blood

Processed Volume:

Specimen will be processed by reference lab facility.


A clean venipuncture is essential. Mix thoroughly by gentle inversion.


Special Processing:

Lab Staff: Do Not centrifuge. Send in original Vacutainer® tube. Store and ship at ambient temperature. Include Mayo Connect Form. Mayo will not process the specimen without this information. Forward promptly.

Patient Preparation:


Sample Rejection:

Specimens other than blood; anticoagulants other than ACD, EDTA or sodium citrate


Reference Range:


An interpretive report will sent.

Critical Values:



This direct mutation analysis will not detect individuals with thrombophilia caused by mechanisms other than the Pt G20210A mutation.

Genetic counseling is recommended before testing asymptomatic family members.

Special Coagulation Clinic/Laboratory, Thrombophilia Center and/or Medical Genetics consultations are available and may be especially helpful in complex cases or in situations in which the diagnosis is atypical or uncertain. Genetic counseling is recommended before testing asymptomatic family members.


Direct Mutation Analysis


Mayo Medical Laboratory Web Page September 2012


3/25/2004: Test moved to Mayo Medical Laboratories from Fairview University Diagnostic Laboratories. Note: Change in CPT coding.
1/23/2006: CPT 2006 updates
2/12/2013: CPT update