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HelpEpic Test Code LAB834 Prothrombin G20210A Mutation, Blood
Additional Codes
MML:PTNT
Ordering Guidance
This assay will only detect the F2 c.*97G>A (rs1799963) variant associated with thrombophilia. To detect other pathogenic alterations in the F2 gene of a patient with a laboratory diagnosis of thrombophilia, order F2NGS / F2 Gene Next Generation Sequencing, Varies.
This assay will not detect alterations in individuals with thrombophilia caused by mechanisms other than the F2 c.*97G>A variant. For those situations consider ordering AATHR / Thrombophilia Profile, Plasma and Whole Blood.
Specimen Required
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Yellow top (ACD solution B), light-blue top (sodium citrate)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send specimen in original tube. Do not aliquot.
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Coagulation Patient Information (T675)
Useful For
Patients with clinically suspected thrombophilia
Determination of the duration of anticoagulation therapy of venous thromboembolism patients
Screening for women contemplating hormone therapy
Genetics Test Information
This test detects the F2 c.*97G>A variant (legacy G20210A).
Special Instructions
Method Name
Direct Variant Analysis
Reporting Name
Prothrombin G20210A Mutation, BSpecimen Type
Whole bloodSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Whole blood | Ambient (preferred) | 14 days | |
| Frozen | 14 days | ||
| Refrigerated | 14 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Extracted DNA | Reject |
Clinical Information
The prothrombin (PT) F2 c.*97G>A (legacy G20210A) variant is a common variant within the 3' untranslated region of the prothrombin gene, affecting 1.5% to 3% of white Americans, especially persons of southern European ancestry. The F2 c.*97G>A variant is less common among African Americans (carrier frequency of 0.4%). The F2 c.*97G>A variant is associated with a 3-fold increased risk of venous thromboembolism due to increased plasma prothrombin activity among carriers.
Reference Values
Negative
Interpretation
The results will be reported as:
-Negative for the c.*97G>A variant
-Heterozygous for the c.*97G>A variant
-Homozygous for the c.*97G>A variant
Cautions
This assay will not detect alterations in individuals with thrombophilia caused by mechanisms other than the prothrombin F2 c.*97G>A variant.
Rare single nucleotide variants under the primers can cause preferential amplification of one allele. In many cases, there is no indication that this interference has occurred. Consequently, the analysis could be done on data from only one allele, which may cause a false-negative result or an incorrect allele frequency (homozygous instead of heterozygous).
Patients receiving allogenic stem cell transplants prior to having blood drawn for DNA based testing may have false-normal or abnormal results depending on the genotype of the stem cell donor.
Consultations with the Mayo Clinic Special Coagulation Clinic Thrombophilia Center, and/or Medical Genetics 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.
Day(s) Performed
Weekly
Report Available
3 to 5 daysSpecimen Retention Time
Whole blood: 2 weeksPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
81240-F2 (prothrombin, coagulation factor II) (eg, hereditary hypercoagulability) gene analysis, 20210G>A variant