- 5 mL of venous blood
- Lavender or pink top tube
Additional information
- Handle sample gently to prevent hemolysis
- Send sample to lab immediately
- Informed consent required prior to the test
- Prothrombin 20210 mutation test is a deoxyribonucleic acid (DNA) analysis test to detect the presence of specific mutation 20210G>A on coagulation factor II (thrombin) gene from blood
- Coagulation factor II (thrombin) gene, also known as F2 gene, is located on the short (p) arm of chromosome 11 at position 11. This gene encodes for the protein prothrombin, which is a coagulation factor essential for normal hemostasis. In response to an injury, prothrombin gets converted to thrombin, which in turn helps in the formation of fibrin leading to clot formation
- Prothrombin 20210 mutation is the substitution of guanylic acid (G) for adenylic acid (A) at nucleotide 20210 in the 3'-untranslated end of the F2 gene causing increased translation, resulting in increased synthesis and secretion of prothrombin, which is characteristic of prothrombin thrombophilia
- Elevated prothrombin increases risk of developing thromboembolic disorders such as deep vein thrombosis (DVT) and pulmonary embolism
- A test for prothrombin 20210 mutation is indicated in the following conditions or circumstances:
- A first venous thromboembolism (VTE) <50 years of age
- A first unprovoked VTE at any age
- Recurrent VTE
- VTE associated with:
- Pregnancy
- The puerperium
- Medications such as oral contraceptives, hormone replacement therapy, selective estrogen receptor modulators (SERM)
- Smoking
- A first VTE with a strong family history
- Women with unexplained fetal loss after 10 weeks of gestation
- Prothrombin thrombophilia may clinically present as:
- Deep vein thrombosis
- Pulmonary embolism
- Recurrent miscarriages
- Early onset severe preeclampsia
- Placental abruption
- Intrauterine growth retardation
- Venous thrombosis at unusual sites such as hepatic, renal, cerebral, pelvis, or retinal veins
- Arterial thrombosis (rare)
- Prothrombin 20210 mutation:
- PT 20210 heterozygous adults have 2-5 fold increased risk of developing recurrent thrombosis
- Heterozygous children have 3-4 fold increased risk of developing recurrent thrombosis
- Women with a prior history of venous thromboembolism (VTE) have a range of 0-15% increased risk of recurrence during pregnancy
- The risk of recurrent VTE in homozygous individuals is unknown but is presumed to be higher than in heterozygotes
- The risk of thrombosis is further increased by another inherited thrombophilic state such as factor V leiden or protein S deficiency or by other risk factors such as use of oral contraceptive and smoking
Additional information
- Prothrombin thrombophilia is more prevalent in Caucasians than in those of other ethnic backgrounds, and is found in 2-5% of European and Middle Eastern populations. Equal in both males and females
- The prevalence of PT 20210 homozygosity is approximately one in 10,000
- Prothrombin 20210 mutation gene testing involves ethical dilemmas, hence genetic counseling is recommended prior to testing
- Factors interfering with the test results include:
- Hemolyzed or frozen blood sample
- Contaminated sample
- Related laboratory and other tests include:
- Anticardiolipin antibodies
- Anti nuclear antigen (ANA)
- Antithrombin
- APC resistance assay
- aPTT
- Factor VIII activity
- Factor XI activity
- Homocysteine
- Protein C
- Protein S
- Prothrombin time (PTT)
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
- Normal result is: Negative for prothrombin 20210 mutation
Increased prothrombin levels caused by prothrombin 20210 mutation may be associated with the following complications:
- Arterial thrombosis, such as stroke, heart attack (rare as compared to venous thrombosis)
- Deep vein thrombosis (DVT)
- Intrauterine growth retardation
- Placental abruption
- Preeclampsia
- Pulmonary embolism (PE)
- Recurrent unexplained miscarriage
- ARUP Consult®. Hypercoagulable States - Thrombophilia. [Homepage on the Internet]©2006-2009. Last updated in December 2008. Last accessed on March 26, 2009. Available at URL: http://www.arupconsult.com/Topics/HematologicDz/Thrombophilia.html
- ARUP Laboratories®. Prothrombin Nucleotide 20210 G/A Gene Mutation (Factor II). [Homepage on the internet]©2006-2009. Last accessed on March 26, 2009. Available at URL:http://www.aruplab.com/guides/ug/tests/0056060.jsp
- Foy P et al. Thrombophilia: 2009 update.
Curr Treat Options Cardiovasc Med. 2009 Apr;11(2):114-28.
- Genetics Home Reference. NLM.NIH.Gov®. F2. [Homepage on the Internet]©2009. Last reviewed in September 2008. Last accessed on March 26, 2009. Available at URL: http://ghr.nlm.nih.gov/gene=f2
- GeneReviews®. Prothrombin Thrombophilia. [Homepage on the Internet]© 1993-2009. Last updated on July 25, 2006. Last accessed on March 26, 2009. Available at URL: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=ptt
- LabTestsOnline®. Factor V Leiden Mutation and PT 20210 Mutation. [Homepage on the Internet]©2001-2009. Last reviewed on August 8, 2007. Last accessed on March 26, 2009. Available at URL: http://labtestsonline.org/understanding/analytes/factor_v_and_pt20210/glance.html
- Naeem MA et al. Prevalence of prothrombin gene mutation (G-A 20210 A) in general population: a pilot study. Clin Appl Thromb Hemost. 2006 Apr;12(2):223-6.
- Whitlatch NL et al. Thrombophilias: when should we test and how does it help? Semin Respir Crit Care Med. 2008 Feb;29(1):25-39.