Test Catalog

Test Id : PTNT

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Prothrombin G20210A Mutation, Blood

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

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
Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test detects the F2 c.*97G>A variant (legacy G20210A).

Method Name
A short description of the method used to perform the test

Direct Variant Analysis

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Prothrombin G20210A Mutation, B

Aliases
Lists additional common names for a test, as an aid in searching

G20210A

Factor II 20210 variant

Prothrombin 20210 varient

Prothrombin nucleotide

Factor II 20210 mutation

Prothrombin mutation

Specimen Type
Describes the specimen type validated for testing

Whole blood

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
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

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)

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

1 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Extracted DNA Reject
 

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred) 14 days
Frozen 14 days
Refrigerated 14 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

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
Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test detects the F2 c.*97G>A variant (legacy G20210A).

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Negative

Interpretation
Provides information to assist in interpretation of the test results

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
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

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.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Poort SR, Rosendaal FR, Reitsma PH, Bertina RM: A common genetic variation in the 3'untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increase in venous thrombosis. Blood. 1996;10:3698-3703

2. Makris M, Preston FE, Beauchamp NJ, et al: Co-inheritance of the 20210 A allele of the prothrombin gene increases the risk of thrombosis in subjects with familial thrombophilia. Thromb Haemost. 1997;78:1426-1429

3. De Stefano V, Martinelli I, Mannucci PM, et al: The risk of recurrent venous thrombosis among heterozygous carriers of both factor V Leiden and the G20210A prothrombin mutation. N Engl J Med. 1999;341:801-806

4. Freed J, Bauer KA: Thrombophilia: clinical and laboratory assessment and management. In: Kitchens CS, Kessler CM, Konkle BA, Streiff MB, Garcia DA, eds. Consultative Hemostasis and Thrombosis. 4th ed. Elsevier; 2019:242-265

Method Description
Describes how the test is performed and provides a method-specific reference

An allelic discrimination assay is set up using TaqMan chemistry. End-products are analyzed using a real-time polymerase chain reaction instrument for genotype detection.(Package insert: TaqMan SNP Genotyping Assays. Applied Biosystems; 2014)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Weekly

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

3 to 5 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

Whole blood: 2 weeks

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

81240-F2 (prothrombin, coagulation factor II) (eg, hereditary hypercoagulability) gene analysis, 20210G>A variant

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
PTNT Prothrombin G20210A Mutation, B 24475-6
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
21803 Prothrombin G20210A Mutation, B 24475-6
21804 PTNT Interpretation 69049-5
21806 PTNT Reviewed By 18771-6

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports