Factor V Leiden With Reflex to R2

TEST: 503853
Test number copied
CPT: 81241
Print Share

Test Includes

Factor V Leiden; reflex to factor V R2 on positives

Expected Turnaround Time

5 - 12 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Related Documents

For more information, please view the literature below.

Procedures for Hemostasis and Thrombosis: A Clinical Test Compendium

    Specimen Requirements

    Specimen

    Whole blood

    Volume

    5 mL

    Minimum Volume

    0.5 mL (Note: This volume does not allow for repeat testing.)

    Container

    Lavender-top (EDTA) tube (preferred) or yellow-top (ACD) tube

    Storage Instructions

    Maintain specimen at room temperature or refrigerate. Stable at room temperature for eight days.

    Causes for Rejection

    Clotted whole blood samples if adequate DNA not obtained; incorrect specimen type; frozen whole blood specimens

    Test Details

    Use

    Detection of the factor V Leiden mutation, followed by testing for the factor V R2 polymorphism in individuals found to be positive for factor V Leiden (heterozygous). These tests provide information about increased risk for venous thrombosis, which can be helpful for prevention and for genetic counseling regarding risk to relatives. The factor V R2 polymorphism does not occur in individuals who are factor V Leiden homozygotes.

    Methodology

    See individual tests.

    Additional Information

    The factor V Leiden mutation causes activated protein C (APC) resistance and increases the risk for venous thrombosis and pulmonary embolism. Heterozygotes (with one copy of the mutation) have a sevenfold increased risk, and homozygotes (with two copies) have a 50% to 80% increased risk. These risks are elevated further by additional genetic defects in naturally occurring anticoagulant proteins (eg, deficiencies of protein C, protein S, or antithrombin) and by situations that tend to provoke thrombosis (eg, major surgery, oral contraceptive use, pregnancy, malignancy, immobility). Factor V Leiden is also associated with increased risk for multiple pregnancy loss. Factor V Leiden is present in 5% to 7% of the general population and 20% to 40% of individuals with venous thrombosis.

    The factor V R2 polymorphism is associated with decreased levels of factor V and it significantly increases risk of venous thrombosis in individuals who are heterozygous for the factor V Leiden mutation. Coexistence of the R2 polymorphism with factor V Leiden increases the risk for venous thrombosis approximately to a 16-fold increased risk. The average age of the first thrombotic event is six years younger in individuals who are heterozygous for both factor V Leiden and the R2 polymorphism than in those with factor V Leiden alone. The R2 polymorphism is common in the general population, with one copy (heterozygous) in 10% of individuals. Among patients with venous thrombosis, approximately 12% are heterozygous for the R2 polymorphism. Indications for testing: Venous thrombosis, pulmonary embolism, peripheral vascular disease (particularly lower extremity occlusive disease), premature stroke or transient ischemic attack, myocardial infarction in female smokers under age 50, women with multiple pregnancy loss. Also, family history of venous thrombosis or a relative known to have the factor V Leiden mutation. Factor V R2 DNA analysis will automatically be performed on the same sample for individuals found to be heterozygous for the factor V Leiden mutation.

    References

    Alhenc-Gelas M, Nicaud V, Gandrille S, et al. The factor V gene A4070G mutation and the risk of venous thrombosis. Thromb Haemost.1999 Feb; 81(2):193-197.10063990
    Castoldi E, Brugge JM, Nicolaes GA, Girelli D, Tans G, Rosing J. Impaired APC cofactor activity of factor V plays a major role in the APC resistance associated with the factor V Leiden (R506Q) and R2 (H1299R) mutations. Blood. 2004 Jun 1; 103(11):4173-4179. 14976057
    Dahlbäck B. Advances in understanding pathogenic mechanisms of thrombophilic disorders. Blood. 2008 Jul 1;112(1):19-27. 18574041
    Faioni EM, Franchi F, Bucciarelli P, et al. Coinheritance of the HR2 haplotype in the factor V gene confers an increased risk of venous thromboembolism to carriers of factor V R506Q (factor V Leiden). Blood. 1999 Nov 1; 94(9):3062-3066. 10556190
    Folsom A, Cushman M, Tsai MY, et al. A prospective study of venous thromboembolism in relation to factor V Leiden and related factors. Blood. 2002 Apr 15; 99(8):2720-2725.
    Grody WW, Griffin JH, Taylor AK, Korf BR, Heit JA; American College of Medical Genetics consensus statement on factor V Leiden mutation testing. Genet Med. 2001 mAR-aPR; 3(2):139-148. 11280951
    Hoekema l, Castoldi E, Tans G, et al. Functional properties of factor V and factor Va encoded by the R2-gene. Thromb Haemost. 2001 Jan; 85(1):75-81. 11204592
    Rosendaal FR, Koster T, Vandenbroucke JP, Reitsma PH. High risk of thrombosis in patients homozygous for factor V Leiden (activated protein C resistance). Blood. 1995 Mar 15, 85(6):1504-1508. 7888671

    LOINC® Map

    Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
    503853 Factor V Leiden Reflex to R2 500587 Factor V Leiden Result 21667-1
    503853 Factor V Leiden Reflex to R2 500628 Methodology: 49549-9
    503853 Factor V Leiden Reflex to R2 500627 Interpretation: 51968-6
    503853 Factor V Leiden Reflex to R2 500629 Comments: 77202-0
    Reflex Table for Interpretation:
    Order Code Order Name Result Code Result Name UofM Result LOINC
    Reflex 1 503940 Factor V R2 DNA Analysis 503942 FV R2 DNA Analysis Result: 41103-3
    Reflex Table for Interpretation:
    Order Code Order Name Result Code Result Name UofM Result LOINC
    Reflex 1 503940 Factor V R2 DNA Analysis 503941 Methodology: 49549-9
    Reflex Table for Interpretation:
    Order Code Order Name Result Code Result Name UofM Result LOINC
    Reflex 1 503940 Factor V R2 DNA Analysis 503944 Interpretation: 35474-6
    Reflex Table for Interpretation:
    Order Code Order Name Result Code Result Name UofM Result LOINC
    Reflex 1 503940 Factor V R2 DNA Analysis 503945 Comment: 77202-0
    Reflex Table for Interpretation:
    Order Code Order Name Result Code Result Name UofM Result LOINC
    Reflex 1 503940 Factor V R2 DNA Analysis 503946 Factor V HR2 Haplotype N/A

    For Providers

    Please login to order a test

    Order a Test

    © 2021 Laboratory Corporation of America® Holdings and Lexi-Comp Inc. All Rights Reserved.

    CPT Statement/Profile Statement

    The LOINC® codes are copyright © 1994-2021, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf