Materiały źródłowe

• #1 Factor V Leiden and activated protein C resistance – UpToDate

  https://www.uptodate.com/contents/factor-v-leiden-and-activated-protein-c-resistance

  Factor V Leiden (FVL) results from a point mutation in the F5 gene, which encodes the factor V protein in the coagulation cascade. FVL renders factor V (both the activated and inactive forms) insensitive to the actions of activated protein C (aPC), a natural anticoagulant. As a result, individuals who carry the FVL variant are at increased risk of venous thromboembolism (VTE). However, FVL is very common in the population, and many individuals with the variant will never have a VTE. For these reasons, the ramifications of carrying FVL may present challenging management decisions, both with respect to primary prevention and prevention of recurrent VTE. […] This topic review discusses the diagnosis of FVL and the management of individuals who carry this variant. A brief overview of FVL genetic testing is presented separately. […] Diagnostic tests: – Choice between genetic testing or functional assay – Genetic testing – Functional aPC resistance assays.

• #2 Treatment for Factor V Leiden, Stuck Between a Rock and a Hard Place: A Case Report and Review of Literature | Jehangir | Journal of Hematology

  https://thejh.org/index.php/jh/article/view/149/103

  Factor V Leiden is a genetically inherited disorder which causes hypercoagulable state that accounts for 40-50% of cases of thrombophilia. The diagnosis of factor V Leiden thrombophilia is made either by using a coagulation screening test or by DNA analysis of F5, which encodes the factor V protein. […] Factor V Leiden thrombophilia is diagnosed either by using a coagulation screening test or by DNA analysis of F5, which encodes the factor V protein. […] Current management of factor V Leiden is based on the clinical manifestations in the patient. […] Long-term management of patients with inherited thrombophilia had not been well studied. […] There needs to be consistent evaluation of individuals on long-term anticoagulation to assess bleeding and assess risks versus benefits in treatment. […] Factor V Leiden remains the most common cause of hypercoagulable states and people with factor V Leiden thrombophilia have a significantly higher-than-average risk of developing venous thromboembolic disease than the general population.

• #3 Factor V Leiden (F5) R506Q Mutation | ARUP Laboratories Test Directory

  https://ltd.aruplab.com/Tests/Pub/0097720

  Order for individuals at risk for Venous thromboembolism (VTE) when results will impact clinical management. […] This test is New York state approved. […] Negative: This sample is negative for factor V Leiden, R506Q mutation. […] The Factor V Leiden (FVL) variant is the most common cause of inherited VTEs, accounting for over 90 percent of activated protein C (APC) resistance. […] Approximately 5 percent of Caucasians, 2 percent of Hispanics, 1 percent of African Americans and 0.5 percent of Asians are heterozygous; homozygosity occurs in 1 in 1500 Caucasians. […] Semidominant; both heterozygotes and homozygotes are at increased risk for VTE. […] Lifetime risk of VTE is 10 percent for heterozygotes and 80 percent for homozygotes. […] The pathogenic gain of function in the F5 gene variant c.1601GA (p.Arg534Gln). […] 20-50 percent of individuals with an isolated VTE have the FVL variant. […] 99 percent. […] This test is not recommended for nonsymptomatic patients under 18 years of age.

• #4 Factor V Leiden

  https://practical-haemostasis.com/Genetics/fv_leiden.html

  Resistance to Activated Protein C [APCr] was first assessed used a modified APTT-based assay. […] A number of methods exist for the detection of the FV Leiden mutation. […] Most techniques can rapidly distinguish heterozygous individuals from those who are homozygous for a mutant allele or wild type [i.e. normal]. […] There are no reference ranges for a genetic test – the mutation is either present in a heterozygous or homozygous form [and rarely a pseudohomozygous form] or it is not. […] The Factor V Leiden mutation is considered the most common inherited thrombophilia risk factor in non-black individuals, with the highest prevalence among whites [3-7%] and the lowest among Asians and Africans [0-1%].

• #5 Factor V Leiden – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/factor-v-leiden/diagnosis-treatment/drc-20372428

  Your doctor may suspect factor V Leiden if you’ve had one or more episodes of abnormal blood clotting or if you have a strong family history of abnormal blood clots. Your doctor can confirm that you have factor V Leiden with a blood test. […] Your doctor may refer you to a specialist in genetic disorders (geneticist) or a specialist in blood disorders (hematologist) for testing to determine whether the cause of your blood clots is genetic and, specifically, whether you have factor V Leiden. […] For factor V Leiden, some basic questions to ask your doctor include: What kinds of tests do I need? Do I need to see a specialist? Does my factor V Leiden need to be treated? Do I need to take medication to prevent additional blood clots? What types of side effects can I expect from the medication? Do I need to limit my activity in any way? If I have children, do they need to be tested?

• #6 Factor V Leiden: Symptoms, Cause, Diagnosis, and Treatment

  https://www.webmd.com/dvt/factor-v-leiden

  Factor V Leiden makes it harder for your clots to break up. If the clots don’t go away, you’re more likely to have them in the veins in your legs. This is called deep vein thrombosis (DVT). […] If you’ve had any of these signs, get checked for factor V Leiden: DVT or PE before turning 50 […] DVT or PE during or right after a pregnancy […] Women who have factor V Leiden are two to three times more likely to lose a baby in the second or third trimester. […] If only one of your parents had this genetic mutation, you’re two to three times more likely to have a DVT than someone without it. If both parents had it, which is rare, your risk rises even more.

• #7 Factor V Leiden Mutation – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK534802/

  Factor V Leiden can be diagnosed by mutation analysis (genetic testing) or using a functional coagulation test for APC resistance. […] Testing for factor V Leiden is indicated for individuals with venous thromboembolism, especially if: […] Genetic testing is indicated for those with a family history of factor V Leiden. It is also preferred for members of a thrombophilic family, patients with antiphospholipid syndrome, or those who need to be on an anticoagulant. […] Mutation testing: Polymerase chain reaction methods can detect factor V Leiden mutation. […] Functional APC resistance assays: These tests cost less than genetic testing, but in rare cases, they can give a misleading, falsely normal result, especially in individuals on therapy with direct thrombin inhibitors or factor Xa inhibitors, as well as in the presence of a lupus anticoagulant.

• #8 Course:MEDG550/Student Activities/Factor V Leiden Thrombophilia – UBC Wiki

  https://wiki.ubc.ca/Course:MEDG550/Student_Activities/Factor_V_Leiden_Thrombophilia

  Diagnosis of factor V Leiden thrombophilia is done using either the APC resistance assay or DNA analysis of the F5 gene. Individuals who are diagnosed using the APC resistance assay should have DNA testing to determine if they carry one or two copies of the factor V Leiden mutation. The following is a list of scenarios where testing for factor V Leiden thrombophilia is recommended by the American College of Medical Genetics: […] first VTE of unknown cause (at any age, but especially younger than 50 years) […] personal history of recurrent VTE […] venous thrombosis at uncommon sites (such as cerebral, mesenteric, portal and hepatic veins) […] VTE during or within a few weeks following pregnancy […] VTE while taking oral contraceptive pills or hormone replacement therapy […] VTE in an individual with a first-degree family member who experienced VTE before the age of 50.

• #9 Factor V Leiden: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/17896-factor-v-leiden

  Laboratory testing (blood tests) diagnose this disorder. Your healthcare provider may suspect you have factor V Leiden if you have a history of venous thromboembolism. They may also suspect it if one or more of your biological family members have a history of blood clots. […] If your provider feels its warranted, theyll order blood tests, including: […] Activated protein C (APC) blood test: This coagulation factor screening test checks if your blood has resistance to activated protein C. This is a protein that prevents factor V from going into overdrive. About 9 in 10 people whose blood is resistant to protein C have the factor V Leiden mutation. […] Genetic testing: If your blood is resistant to protein C, your provider will order genetic testing to check your F5 gene for the factor V Leiden mutation. In some cases, providers order this test without first ordering an APC blood test. […] Simply having a family history of blood clots may not be reason enough to run these tests. Your provider will advise you on whether you need testing, as well as on the pros and cons of testing.

• #10 Factor V Leiden thrombophilia | Genetics in Medicine

  https://www.nature.com/articles/gim920112

  Factor V Leiden is a genetic disorder characterized by a poor anticoagulant response to activated Protein C and an increased risk for venous thromboembolism. […] Diagnosis requires the activated Protein C resistance assay (a coagulation screening test) or DNA analysis of the F5 gene, which encodes the Factor V protein. […] The diagnosis of Factor V Leiden requires the APC resistance assay, a coagulation screening test, or DNA analysis of F5, the gene encoding Factor V, to identify the Leiden mutation, a specific G-to-A substitution at nucleotide 1691 that predicts a single-amino-acid replacement (R506Q). […] The APC resistance assay involves performing an activated partial thromboplastin time (aPTT) on the individual’s plasma in the presence and absence of a standardized amount of exogenous APC; the two results are expressed as a ratio (aPTT + APC/aPTT APC).

• #11 Factor V Leiden thrombophilia | Genetics in Medicine

  https://www.nature.com/articles/gim920112

  Factor V Leiden is a genetic disorder characterized by a poor anticoagulant response to activated Protein C and an increased risk for venous thromboembolism. […] Diagnosis requires the activated Protein C resistance assay (a coagulation screening test) or DNA analysis of the F5 gene, which encodes the Factor V protein. […] The diagnosis of Factor V Leiden requires the APC resistance assay, a coagulation screening test, or DNA analysis of F5, the gene encoding Factor V, to identify the Leiden mutation, a specific G-to-A substitution at nucleotide 1691 that predicts a single-amino-acid replacement (R506Q). […] The APC resistance assay involves performing an activated partial thromboplastin time (aPTT) on the individual’s plasma in the presence and absence of a standardized amount of exogenous APC; the two results are expressed as a ratio (aPTT + APC/aPTT APC).

• #12

  https://journals.lww.com/ijpm/fulltext/2020/63020/comparative_analysis_of__aptt_vs_rvvt__based.17.aspx

  Thrombophilia is a hypercoagulable state characterized by increased venous thrombosis. The main objective of this study is to compare the sensitivity of activated partial thromboplastin time (APTT) vs dilute Russell viper venom test (DRVVT) based APCR assays with predilution in Factor V-deficient plasma for diagnosis of Factor V Leiden mutation. The sensitivity of screening APTT-based APCR for detection of Factor V Leiden mutation is 67% and for the noncarrier state, it is 62%. The sensitivity of modified APTT and DRVVT with predilution in FV-deficient plasma for detection of Factor V Leiden mutation is 82% and 84%, respectively. Modified DRVVT with predilution in FV-deficient plasma is more sensitive than screening and modified APTT-based APCR test in the diagnosis of Factor V Leiden mutation and the former test can distinguish homozygous and heterozygous states from normal individuals. The first generation assay for screening APCR was initially described by Dahlback (1995) and is based on APTT assay and its prolongation by addition of APC. Second generation tests are modified APTT and modified DRVVT-based APCR assays for differentiating normal individuals from homozygous and heterozygous state of Factor V Leiden mutation. Screening APTT test is increased in activated protein C resistance due to Factor V Leiden mutation as well as acquired causes such as patients on direct-acting oral anticoagulants, warfarin, lupus anticoagulants, and oral contraceptive pills which are independent risk factors of venous thrombosis. Modified APTT with predilution in FV-deficient plasma is independent of these confounding factors and specific for factor V Leiden mutation. The Gold standard for diagnosis of Factor V Leiden mutation is by PCR technique but this is not cost-effective. Overall Sensitivity of Screening APTT-based APCR test for detection of FV Leiden mutation is 67%, for heterozygous state sensitivity is 69%, and for the homozygous state, it is 64%. The overall sensitivity of modified APTT with predilution in FV-deficient plasma (1:4), based APCR test for detection of FV Leiden mutation is 82%, for heterozygous state sensitivity is 84% and for the homozygous state is 77%. The sensitivity of modified DRVVT with predilution in FV-deficient plasma (1:4), based APCR test for detection of FV Leiden mutation is 84%, for heterozygous state sensitivity is 86%, and for Homozygous state, it is 80%. The present study showed that Modified DRVVT is more sensitive than screening and modified APTT-based APCR assay in the diagnosis of Factor V Leiden mutation patients presenting with features of venous thrombosis and pulmonary embolism as well as in asymptomatic individuals. Modified DRVVT offers extra-advantage of identifying LAC cases (sensitivity = 90%), patients on warfarin and is independent of factor VIII, IX, XI, and XII levels. Modified DRVVT is more sensitive than screening and modified APTT based APCR assay in the diagnosis of Factor V Leiden mutation and offers extra-advantage of identifying LAC cases and can distinguish normal cases from homozygous and heterozygous state of Factor V Leiden mutation.

• #13 Factor V Leiden Mutation and PT 20210 Mutation – Testing.com

  https://www.testing.com/tests/factor-v-leiden-mutation-and-pt-20210-mutation/

  If genetic testing indicates that an individual has one factor V Leiden or PT 20210 gene copy, then the person is heterozygous; if there are two copies, then the person is homozygous for the mutation. […] The risk of excessive clotting from these mutation(s) varies from person to person. If you are asymptomatic, you may never have a DVT and/or VTE. If you have had one or more blood clots, then the mutation(s) is the most likely cause and you have an increased risk for another clot. If no mutations are found, then it is likely that the condition is due to another cause. […] Sometimes, evaluation for the presence of a factor V Leiden mutation can begin with a test for activated protein C (APC) resistance, though it is not commonly performed nowadays. About 90% of the time, APC resistance is due to a factor V Leiden mutation, and the APC resistance ratio assay has a greater than 99% sensitivity for detecting a factor V Leiden mutation. If resistance is present, then a test for the factor V Leiden gene mutation is performed on the person’s DNA, both to confirm the diagnosis and to determine whether the person has one or two copies of the mutation (is heterozygous or homozygous for the mutation).

• #14 Factor V Leiden Mutation | MLabs

  https://mlabs.umich.edu/tests/factor-v-leiden-mutation

  Allelic Discrimination, Polymerase Chain Reaction (PCR) […] Resistance of FVa to degradation by APC is associated with an increased risk of venous thromboemobolism (VTE). […] This resistance is caused by a specific point mutation in the gene coding for the coagulation factor V (F5 c.1601GA; rs6025; g.169549811CT; NC_000001.11; NM_000130.4; previously designated c.1691GA) which results in the replacement of amino acid Arg 534 (CGA) by Gln (CAA) (F5 R534Q; previously designated R506Q R506Q Leiden). […] This amino acid substitution prevents inactivation of factor Va by APC. […] Genetic counseling may be indicated.

• #15 F5DNA – Overview: Factor V Leiden (R506Q) Mutation, Blood

  https://www.mayocliniclabs.com/test-catalog/overview/81419

  Patients with clinically suspected thrombophilia and: 1. Activated protein C (APC)-resistance either proven or suspected by a low or borderline APC-resistance ratio or 2. A family history of factor V Leiden […] This test detects the F5 c.1601G>A; p.Arg534Gln variant (legacy R506Q). […] This assay will only detect the F5 c.1601G>A; p.Arg534Gln (rs6025) variant associated with factor V Leiden thrombophilia. […] This assay will not detect alterations in individuals with activated protein C (APC)-resistance caused by mechanisms other than the F5:c.1601G>A, p.Arg534Gln variant. […] The results will be reported as: -Negative for the F5 c.1601G>A, p.Arg534Gln variant -Heterozygous for the F5 c.1601G>A, p.Arg534Gln variant -Homozygous for the F5 c.1601G>A, p.Arg534Gln variant. […] This assay will only detect the genetic basis for activated protein C (APC)-resistance due to the F5 c.1601G>A, p.Arg534Gln variant. This assay will not detect the genetic basis for APC resistance due to other variants nor the acquired APC resistance.

• #16 Factor V Leiden – Wikipedia

  https://en.wikipedia.org/wiki/Factor_V_Leiden

  Factor V Leiden is an autosomal dominant genetic condition that exhibits incomplete penetrance, i.e. not every person who has the mutation develops the disease. […] Suspicion of factor V Leiden being the cause for any thrombotic event should be considered in any Caucasian patient below the age of 45, or in any person with a family history of venous thrombosis. There are a few different methods by which this condition can be diagnosed. Most laboratories screen 'at risk’ patients with either a snake venom (e.g. dilute Russell’s viper venom time) based test or an aPTT based test. In both methods, the time it takes for blood to clot is decreased in the presence of the factor V Leiden mutation. This is done by running two tests simultaneously; one test is run in the presence of activated protein C and the other, in the absence. A ratio is determined based on the two tests and the results signify to the laboratory whether activated protein C is working or not. There is also a genetic test that can be done for this disorder. The mutation (a 1691GA substitution) removes a cleavage site of the restriction endonuclease MnlI, so PCR, treatment with MnlI, and then DNA electrophoresis will give a diagnosis. Other PCR based assays such as iPLEX can also identify zygosity and frequency of the variant.

• #17 Factor V deficiency | Great Ormond Street Hospital

  https://www.gosh.nhs.uk/conditions-and-treatments/conditions-we-treat/factor-v-deficiency/

  Factor V deficiency diagnosis can be diagnosed using a sample of blood for testing in the laboratory. A test to measure how long a sample takes to clot may suggest a clotting disorder, which would then be investigated further. The level of Factor V in the blood will be checked as well as the level of Factor VIII as these sometimes occur in combination resulting in a different pattern of bleeding. […] Factor V deficiency can be diagnosed before birth (prenatally) if there is a family history. There are several options for this including chorionic villus sampling (CVS) early in pregnancy or amniocentesis around 15 to 20 weeks.

• #18 Factor V Leiden Mutation and PT 20210 Mutation – Testing.com

  https://www.testing.com/tests/factor-v-leiden-mutation-and-pt-20210-mutation/

  Factor V Leiden (FVL) mutation and prothrombin 20210 (PT 20210) mutation tests are two tests often used together to help diagnose the cause of inappropriate blood clot (thrombus) formation, including deep vein thrombosis (DVT) and/or venous thromboembolism (VTE). […] Testing for factor V Leiden and PT 20120 mutations is used to help determine if an individual has inherited a disorder associated with blood clots and can determine whether the person has one copy or two copies of the mutation (heterozygous or homozygous.) […] These tests may be ordered to help determine the reason for an initial harmful blood clot (thrombotic episode), especially when it occurs in a person under 50 years old, is unprovoked, or is in an unusual place such as the liver (hepatic), the kidneys (renal), the brain (cerebral), the gut and pelvis (mesenteric), or in the eye veins.

• #19 Factor V Leiden – Blood Clots

  https://www.stoptheclot.org/learn_more/factor-v-leiden-2/

  A blood test (called a screening test) can show if you have activated protein C resistance. If you do, another blood test that examines your genes (called DNA) will be done to find out if factor V Leiden is the cause of the resistance and what type of factor V Leiden you have. […] Some hospitals do only the DNA test and not the screening test.

• #20 What is Factor V Leiden test and its Uses, Results, and Normal Range?

  https://www.yashodahospitals.com/diagnostics/factor-v-leiden-test/

  Factor V Leiden test is used to diagnose the abnormal form of Factor V. […] The Factor V Leiden test is used to diagnose a type of mutant Factor V, which causes hypercoagulability of blood. […] If your test results show the presence of activated protein C resistance along with the presence of the prothrombin 20210 (PT 20210) gene in your report, it means that you have a presence of Factor V Leiden in your blood. […] If you are under 50 and tend to develop abnormal blood clots along with a family history of DVT, you may need to get tested for the factor V Leiden test. […] There are no special instructions to follow before this diagnostic test. […] A Factor V Leiden test might take 5-8 days, depending upon the laboratory where the test is conducted. […] Usually, two tests are done to diagnose the factor, V Leiden, in the blood: blood screening and DNA testing to check the genetic predisposition of this disease.

• #21 Factor V Leiden – Blood Clots

  https://www.stoptheclot.org/learn_more/factor-v-leiden-2/

  A blood test (called a screening test) can show if you have activated protein C resistance. If you do, another blood test that examines your genes (called DNA) will be done to find out if factor V Leiden is the cause of the resistance and what type of factor V Leiden you have. […] Some hospitals do only the DNA test and not the screening test.

• #22 Factor V Leiden thrombophilia | Genetics in Medicine

  https://www.nature.com/articles/gim920112

  When clinical care requires testing for Factor V Leiden, either direct DNA-based genotyping or a modified APC resistance assay is recommended. […] The decision to test selected patients should be based on the likelihood that the results are likely to influence treatment. […] Testing is appropriate in selected individuals with the following: A first unprovoked VTE at any age (especially age 50 years). […] There is a general consensus that Factor V Leiden testing may have utility in certain circumstances. […] However, guidelines differ on the specific indications for testing. […] Specific informed consent is not generally required for Factor V Leiden genetic testing, although it may be required in some states.

• #23 F5DNA – Overview: Factor V Leiden (R506Q) Mutation, Blood

  https://www.mayocliniclabs.com/test-catalog/overview/81419

  Patients with clinically suspected thrombophilia and: 1. Activated protein C (APC)-resistance either proven or suspected by a low or borderline APC-resistance ratio or 2. A family history of factor V Leiden […] This test detects the F5 c.1601G>A; p.Arg534Gln variant (legacy R506Q). […] This assay will only detect the F5 c.1601G>A; p.Arg534Gln (rs6025) variant associated with factor V Leiden thrombophilia. […] This assay will not detect alterations in individuals with activated protein C (APC)-resistance caused by mechanisms other than the F5:c.1601G>A, p.Arg534Gln variant. […] The results will be reported as: -Negative for the F5 c.1601G>A, p.Arg534Gln variant -Heterozygous for the F5 c.1601G>A, p.Arg534Gln variant -Homozygous for the F5 c.1601G>A, p.Arg534Gln variant. […] This assay will only detect the genetic basis for activated protein C (APC)-resistance due to the F5 c.1601G>A, p.Arg534Gln variant. This assay will not detect the genetic basis for APC resistance due to other variants nor the acquired APC resistance.

• #24 Factor V Leiden and PT 20210

  https://labtestsonline.org.uk/tests/factor-v-leiden-mutation-and-pt-20210-mutation

  Different laboratories may use different screening techniques to detect these variants. […] If a person is found to have a resistance to APC through testing, they may be at an increased risk for thrombosis. […] The factor V Leiden mutation should be confirmed with genetic testing. […] If genetic testing shows one factor V Leiden gene copy, then the patient is heterozygous; if there are two copies, then the patient is homozygous. […] The implications of a positive thrombophilia screen for an affected individual is complicated and should be discussed with a specialist haematologist. […] The current UK guidelines do not advise testing for Factor V Leiden or prothrombin G201210A mutations after a VTE as presence or absence of these mutations does not influence treatment or help describe the risk of recurrent thrombosis.

• #25 About Factor V Leiden Thrombophilia

  https://www.genome.gov/Genetic-Disorders/Factor-V-Leiden-Thrombophilia

  Your doctor would suspect a diagnosis of thrombophilia if you have a history of venous thrombosis and/or a family history of venous thrombosis. The diagnosis is made using a screening test called a coagulation screening test or by genetic testing (DNA analysis) of the F5 gene. […] Factor V Leiden is the most common inherited form of thrombophilia. The risk of developing a clot in a blood vessel depends on whether a person inherits one or two copies of the factor V Leiden mutation. Inheriting one copy of the mutation from a parent increases by fourfold to eightfold the chance of developing a clot. People who inherit two copies of the mutation, one from each parent, may have up to 80 times the usual risk of developing this type of blood clot. Considering that the risk of developing an abnormal blood clot averages about 1 in 1,000 per year in the general population, the presence of one copy of the factor V Leiden mutation increases that risk to 1 in 125 to 1 in 250. Having two copies of the mutation may raise the risk as high as 1 in 12.

• #26 Factor V Leiden (F5) R506Q Mutation | ARUP Laboratories Test Directory

  https://ltd.aruplab.com/Tests/Pub/0097720

  Order for individuals at risk for Venous thromboembolism (VTE) when results will impact clinical management. […] This test is New York state approved. […] Negative: This sample is negative for factor V Leiden, R506Q mutation. […] The Factor V Leiden (FVL) variant is the most common cause of inherited VTEs, accounting for over 90 percent of activated protein C (APC) resistance. […] Approximately 5 percent of Caucasians, 2 percent of Hispanics, 1 percent of African Americans and 0.5 percent of Asians are heterozygous; homozygosity occurs in 1 in 1500 Caucasians. […] Semidominant; both heterozygotes and homozygotes are at increased risk for VTE. […] Lifetime risk of VTE is 10 percent for heterozygotes and 80 percent for homozygotes. […] The pathogenic gain of function in the F5 gene variant c.1601GA (p.Arg534Gln). […] 20-50 percent of individuals with an isolated VTE have the FVL variant. […] 99 percent. […] This test is not recommended for nonsymptomatic patients under 18 years of age.

• #27 Factor V Leiden – Wikipedia

  https://en.wikipedia.org/wiki/Factor_V_Leiden

  Factor V Leiden is an autosomal dominant genetic condition that exhibits incomplete penetrance, i.e. not every person who has the mutation develops the disease. […] Suspicion of factor V Leiden being the cause for any thrombotic event should be considered in any Caucasian patient below the age of 45, or in any person with a family history of venous thrombosis. There are a few different methods by which this condition can be diagnosed. Most laboratories screen 'at risk’ patients with either a snake venom (e.g. dilute Russell’s viper venom time) based test or an aPTT based test. In both methods, the time it takes for blood to clot is decreased in the presence of the factor V Leiden mutation. This is done by running two tests simultaneously; one test is run in the presence of activated protein C and the other, in the absence. A ratio is determined based on the two tests and the results signify to the laboratory whether activated protein C is working or not. There is also a genetic test that can be done for this disorder. The mutation (a 1691GA substitution) removes a cleavage site of the restriction endonuclease MnlI, so PCR, treatment with MnlI, and then DNA electrophoresis will give a diagnosis. Other PCR based assays such as iPLEX can also identify zygosity and frequency of the variant.

• #28 Factor V Leiden Mutation and PT 20210 Mutation – Testing.com

  https://www.testing.com/tests/factor-v-leiden-mutation-and-pt-20210-mutation/

  If genetic testing indicates that an individual has one factor V Leiden or PT 20210 gene copy, then the person is heterozygous; if there are two copies, then the person is homozygous for the mutation. […] The risk of excessive clotting from these mutation(s) varies from person to person. If you are asymptomatic, you may never have a DVT and/or VTE. If you have had one or more blood clots, then the mutation(s) is the most likely cause and you have an increased risk for another clot. If no mutations are found, then it is likely that the condition is due to another cause. […] Sometimes, evaluation for the presence of a factor V Leiden mutation can begin with a test for activated protein C (APC) resistance, though it is not commonly performed nowadays. About 90% of the time, APC resistance is due to a factor V Leiden mutation, and the APC resistance ratio assay has a greater than 99% sensitivity for detecting a factor V Leiden mutation. If resistance is present, then a test for the factor V Leiden gene mutation is performed on the person’s DNA, both to confirm the diagnosis and to determine whether the person has one or two copies of the mutation (is heterozygous or homozygous for the mutation).

• #29 Factor V Leiden thrombophilia: MedlinePlus GeneticsLock

  https://medlineplus.gov/genetics/condition/factor-v-leiden-thrombophilia/

  Factor V Leiden thrombophilia is an inherited disorder of blood clotting. […] The factor V Leiden mutation is associated with a slightly increased risk of pregnancy loss (miscarriage). […] The chance of developing an abnormal blood clot depends on whether a person has one or two copies of the factor V Leiden mutation in each cell. […] Genetic Testing Registry: Thrombophilia due to activated protein C resistance. […] American College of Medical Genetics consensus statement on factor V Leiden mutation testing.

• #30 Factor V Leiden: Symptoms, Cause, Diagnosis, and Treatment

  https://www.webmd.com/dvt/factor-v-leiden

  Factor V Leiden makes it harder for your clots to break up. If the clots don’t go away, you’re more likely to have them in the veins in your legs. This is called deep vein thrombosis (DVT). […] If you’ve had any of these signs, get checked for factor V Leiden: DVT or PE before turning 50 […] DVT or PE during or right after a pregnancy […] Women who have factor V Leiden are two to three times more likely to lose a baby in the second or third trimester. […] If only one of your parents had this genetic mutation, you’re two to three times more likely to have a DVT than someone without it. If both parents had it, which is rare, your risk rises even more.

• #31 Factor V Leiden Genotype Test – Boston Heart

  https://bostonheartdiagnostics.com/test/factor-v-leiden/

  Factor V Leiden genotype is a variant form of factor V with a change in one of the amino acids resulting in increased clot formation. The intended use of Factor V Leiden testing is as an aid in selection of appropriate thrombosis prevention regimens. The genetic test identifies individuals with defects in clotting factors, thus allowing the physician to determine the need for more aggressive thrombosis prevention measures for these individuals. […] Genotype -/- normal risk of clot formation. […] Genotypes +/- increased risk of developing clots, especially if on oral estrogen therapy. […] Genotype +/+ markedly increased risk of developing clots, especially if on oral estrogen therapy. […] Genotypes +/-, +/+ consider low dose aspirin treatment.

• #32 Factor V Leiden and Prothrombin Gene Mutation

  https://www.gloshospitals.nhs.uk/our-services/services-we-offer/pathology/tests-and-investigations/factor-v-leiden-and-prothrombin-gene-mutation/

  For Factor V Leiden and Prothrombin mutation investigations as part of a full Thrombophilia screen, please see the Thrombophilia screen test page. […] This test is intended to detect Prothrombin (G20210A) and Factor V Leiden (G1691A) mutations as an aid to the diagnosis of individuals with suspected thrombophilia. […] The G1691A mutation in the Factor V gene (known as Factor V Leiden) causes Factor V resistance to cleavage and inactivation by Activated Protein C. This mutation is present in 5% of the general population. […] This test cannot usually be added on to a previous request as, unless the sample is frozen quickly, the DNA used for Factor V and Prothrombin gene PCR begins to degrade.

• #33 511154: Factor V Leiden Mutation Analysis | Labcorp

  https://www.labcorp.com/tests/511154/factor-v-leiden-mutation-analysis

  Test Number 511154Test number copied CPT 81241 Synonyms […] Methodology […] Allele-specific polymerase chain reaction (PCR) […] Result Turnaround Time […] 5 – 7 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. […] Use […] Contributes to the risk assessment for venous thromboembolism (VTE) to better inform decisions regarding treatment and clinical management decisions of patients with relevant personal history of VTE and potential preventative care for patients with significant family history of VTE. […] Limitations […] Variant analyzed: c.1601GA (p.Arg534Gln), referred to as Factor V Leiden; NM_000130.5. Results must be combined with clinical information for the most accurate interpretation. Molecular-based testing is highly accurate, but as in any laboratory test, diagnostic errors may occur. False positive or false negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, somatic or tissue-specific mosaicism, mislabeled samples, or erroneous representation of family relationships.

• #34 What is Factor V Leiden test and its Uses, Results, and Normal Range?

  https://www.yashodahospitals.com/diagnostics/factor-v-leiden-test/

  Factor V Leiden test is used to diagnose the abnormal form of Factor V. […] The Factor V Leiden test is used to diagnose a type of mutant Factor V, which causes hypercoagulability of blood. […] If your test results show the presence of activated protein C resistance along with the presence of the prothrombin 20210 (PT 20210) gene in your report, it means that you have a presence of Factor V Leiden in your blood. […] If you are under 50 and tend to develop abnormal blood clots along with a family history of DVT, you may need to get tested for the factor V Leiden test. […] There are no special instructions to follow before this diagnostic test. […] A Factor V Leiden test might take 5-8 days, depending upon the laboratory where the test is conducted. […] Usually, two tests are done to diagnose the factor, V Leiden, in the blood: blood screening and DNA testing to check the genetic predisposition of this disease.

• #35 511154: Factor V Leiden Mutation Analysis | Labcorp

  https://www.labcorp.com/tests/511154/factor-v-leiden-mutation-analysis

  Test Number 511154Test number copied CPT 81241 Synonyms […] Methodology […] Allele-specific polymerase chain reaction (PCR) […] Result Turnaround Time […] 5 – 7 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. […] Use […] Contributes to the risk assessment for venous thromboembolism (VTE) to better inform decisions regarding treatment and clinical management decisions of patients with relevant personal history of VTE and potential preventative care for patients with significant family history of VTE. […] Limitations […] Variant analyzed: c.1601GA (p.Arg534Gln), referred to as Factor V Leiden; NM_000130.5. Results must be combined with clinical information for the most accurate interpretation. Molecular-based testing is highly accurate, but as in any laboratory test, diagnostic errors may occur. False positive or false negative results may occur for reasons that include genetic variants, blood transfusions, bone marrow transplantation, somatic or tissue-specific mosaicism, mislabeled samples, or erroneous representation of family relationships.

• #36 F5DNA – Overview: Factor V Leiden (R506Q) Mutation, Blood

  https://www.mayocliniclabs.com/test-catalog/overview/81419

  Patients with clinically suspected thrombophilia and: 1. Activated protein C (APC)-resistance either proven or suspected by a low or borderline APC-resistance ratio or 2. A family history of factor V Leiden […] This test detects the F5 c.1601G>A; p.Arg534Gln variant (legacy R506Q). […] This assay will only detect the F5 c.1601G>A; p.Arg534Gln (rs6025) variant associated with factor V Leiden thrombophilia. […] This assay will not detect alterations in individuals with activated protein C (APC)-resistance caused by mechanisms other than the F5:c.1601G>A, p.Arg534Gln variant. […] The results will be reported as: -Negative for the F5 c.1601G>A, p.Arg534Gln variant -Heterozygous for the F5 c.1601G>A, p.Arg534Gln variant -Homozygous for the F5 c.1601G>A, p.Arg534Gln variant. […] This assay will only detect the genetic basis for activated protein C (APC)-resistance due to the F5 c.1601G>A, p.Arg534Gln variant. This assay will not detect the genetic basis for APC resistance due to other variants nor the acquired APC resistance.

• #37 Factor V Leiden Mutation and PT 20210 Mutation – Testing.com

  https://www.testing.com/tests/factor-v-leiden-mutation-and-pt-20210-mutation/

  To determine whether you have an inherited gene mutation that increases your risk of developing a blood clot, including a deep venous thrombosis (DVT) and/or venous thromboembolism (VTE) […] When you have had an unexplained blood clot (thrombotic episode), especially when you are less than 50 years old, have recurrent DVT or VTE episodes, experienced DVT or VTE during pregnancy, had DVT at unusual sites, or have a strong family history of thrombosis […] Factor V Leiden and prothrombin 20210 (PT 20210 or Factor II mutation) are genetic mutations that are associated with an increased risk of developing inappropriate blood clots. These mutations are tested by two separate tests that evaluate a person’s DNA to look for the mutations. The two tests are often performed together to help determine if an individual has an inherited risk for excessive clotting.

• #38 Factor V Leiden Functional Assay | RT Diagnostics

  https://rtdiagnostics.net/factor-v-leiden-functional-assay

  Factor V Leiden is a mutated form of factor V, the reason behind blood clotting disorders. This blood test is used to screen for the defective gene (eg. Mutation) that causes an inappropriate blood clot (Venous Thrombosis). […] Factor V is also called Leiden factor because it was originally discovered at the University of Leiden (Netherlands), hence known also as Factor V Leiden – FVL, Leiden Clotting Factor etc. Factor V Leiden thrombophilia is an inherited disorder of blood clotting. […] Factor V Leiden test is performed in suspected patients with abnormal clots. This test is indicated by a physician when the patient had episodes of abnormal clotting history in the past following injuries and/or if the patient has a strong family genetic history of abnormal blood clots (thrombotic episodes). […] Additional tests include lupus anticoagulant, protein C, Protein S, Antithrombin, Homocysteine, Factor V gene R2 mutation, Methylenetetrahydrofolate reductase (MTHFR) gene mutation etc. Other tests include stool tests and urinalysis, genetic testing etc.

• #39 Factor V (Leiden) Mutation Analysis with Reflex to HR2 Mutation Analysis | Test Detail | Quest Diagnostics

  https://testdirectory.questdiagnostics.com/test/test-detail/17904/factor-v-leiden-mutation-analysis-with-reflex-to-hr2-mutation-analysis?p=r&cc=MASTER

  Factor V (Leiden) Mutation Analysis with Reflex to HR2 Mutation Analysis – This test detects the factor V Leiden variant, the most common cause of inherited thrombophilia; it may be used to evaluate individuals with a strong personal or family history of venous thromboembolism (VTE) and inform treatment or preventive decisions. […] Testing the factor V R2 variant in factor V Leiden heterozygous patients helps assess additional risk of VTE. […] This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

• #40 F5DNA – Overview: Factor V Leiden (R506Q) Mutation, Blood

  https://www.mayocliniclabs.com/test-catalog/overview/81419

  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.

• #41 Factor V Leiden Information – Milton Keynes University Hospital

  https://www.mkuh.nhs.uk/patient-information-leaflet/factor-v-leiden-information

  The gene for Factor V Leiden can be found in a blood sample. […] A heterozygote has a 50/50 chance of passing the abnormal gene to their children. A child of a homozygote will inherit at least one factor V Leiden gene.

• #42 Factor V (Leiden) Mutation Analysis | Test Detail | Quest Diagnostics

  https://testdirectory.questdiagnostics.com/test/test-detail/17900/factor-v-leiden-mutation-analysis?p=r&cc=MASTER

  Factor V (Leiden) Mutation Analysis – This test detects the factor V Leiden variant, the most common cause of inherited thrombophilia; it may be used to evaluate individuals with a strong personal or family history of venous thromboembolism (VTE) and inform treatment or preventive decisions. […] Factor V Leiden refers to the c.1691G>A variant in the FV gene, which encodes coagulation factor V. This variant results in resistance to factor V protein degradation by activated protein C and increases the risk of VTE 6 to 8 fold in heterozygous carriers and 80 fold in homozygous carriers. […] This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

• #43 511154: Factor V Leiden Mutation Analysis | Labcorp

  https://www.labcorp.com/tests/511154/factor-v-leiden-mutation-analysis

  This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration. […] Genetic coordinators are available for health care providers to discuss results and for information on how to order additional testing, if desired, at 1-800-345-GENE.

• #44 Does Medicare Cover Factor V Leiden Testing? – Medicare.org

  https://www.medicare.org/articles/does-medicare-cover-factor-v-leiden-testing/

  Does Medicare Cover Factor V Leiden Testing? […] Because deep vein thrombosis and pulmonary embolism are serious enough to be life threatening, if you suspect that you have the genetic mutation of factor V, factor V Leiden, you should be tested to determine your risk factor for thrombophilia. […] In order to find out if you have factor V Leiden, a screening can be done by taking a sample of your blood to test for activated protein C resistance. A positive result may mean that you have the factor V Leiden mutation. […] Statistics indicate that factor V Leiden is the most common inherited form of thrombophilia in the United States and Europe among Caucasians. Fortunately, Medicare recipients have coverage for the necessary blood test needed to screen for this condition. […] Under both Original Medicare Parts A and B, your Medicare benefits offer coverage for blood tests that your health care provider orders to diagnose or monitor a condition or a disease. These blood tests must be medically necessary for Medicare recipients to receive coverage.

• #45 Factor V Leiden ICD-10-CM Codes | 2023

  https://www.carepatron.com/icd/factor-v-leiden

  Factor V Leiden is a mutation of one of the clotting factors in the blood, leading to an increased risk of developing abnormal blood clots. […] The ICD-10-CM classification system provides specific codes for this genetic condition. […] The Factor V Leiden ICD-10-CM code should be utilized in medical records when diagnosing, treating, or documenting a patient known to have this particular genetic predisposition to increased clotting. […] Factor V Leiden is usually diagnosed via a blood test, which may be prompted due to a personal or familial history of blood clots, or when other indicators of heightened clotting risk are evident. […] A diagnosis code for Factor V Leiden offers a standardized manner to indicate that a patient possesses this specific genetic mutation increasing their risk of abnormal blood clots. This standardized coding aids in clinical care, research, and administrative functions like billing and insurance claims processing.

• #46 2025 ICD-10-CM Diagnosis Code D68.51: Activated protein C resistance

  https://www.icd10data.com/ICD10CM/Codes/D50-D89/D65-D69/D68-/D68.51

  D68.51 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. […] Factor V Leiden mutation […] A hemostatic disorder characterized by a poor anticoagulant response to activated protein c (apc). The activated form of factor v (factor va) is more slowly degraded by activated protein c. Factor v leiden mutation (r506q) is the most common cause of apc resistance. […] An abnormality that refers to mutation of factor v leiden, which is a variant of human factor v. It results in thrombophilia, deep vein thrombosis, and a slightly increased risk of miscarriage. […] activated protein C resistance D68.51 […] factor V Leiden mutation D68.51.

• #47 Factor V Leiden thrombophilia | Genetics in Medicine

  https://www.nature.com/articles/gim920112

  When clinical care requires testing for Factor V Leiden, either direct DNA-based genotyping or a modified APC resistance assay is recommended. […] The decision to test selected patients should be based on the likelihood that the results are likely to influence treatment. […] Testing is appropriate in selected individuals with the following: A first unprovoked VTE at any age (especially age 50 years). […] There is a general consensus that Factor V Leiden testing may have utility in certain circumstances. […] However, guidelines differ on the specific indications for testing. […] Specific informed consent is not generally required for Factor V Leiden genetic testing, although it may be required in some states.

• #48 LCD – MolDX: Genetic Testing for Hypercoagulability / Thrombophilia (Factor V Leiden, Factor II Prothrombin, and MTHFR) (L36155)

  https://www.cms.gov/medicare-coverage-database/view/lcd.aspx?lcdid=36155

  IndicationsThis is a non-coverage policy for genetic testing for thrombophilia testing for the Factor V Leiden (FVL) variant in the F5 gene, the G20210GA (G20210A) variant in the F2 gene, and the MTHFR gene which encodes the 5,10-methylenetetrahydrofolate reductase enzyme. […] Testing for FVL and F2 G20210A mutations is indicated for pregnant patients who have a history of personal venous thromboembolism (VTE) associated with a non-recurrent (transient) risk factor who are not otherwise receiving anticoagulant prophylaxis. […] The results of genetic testing can inform risk stratification for VTE recurrence and subsequent need for antenatal prophylaxis. […] Genetic testing is available for a number of types of inherited thrombophilia, including mutations in the FVL, F2 and MTHFR genes. However, the clinical utility of testing is uncertain.

• #49 Factor V Leiden: Signs, Symptoms, Treatments, and Risk Factors

  https://www.businessinsider.com/guides/health/reproductive-health/factor-v-leiden

  Factor V Leiden is a genetic blood clotting disorder. […] „Testing for this mutation is nearly always done when a patient has a blood clot or certain pregnancy complications, including multiple first-trimester miscarriages, a miscarriage for unknown reasons after 10 weeks of pregnancy, stillbirth, unexplained severe preeclampsia, placental abruption, or a fetus with severe growth restriction,” says Kate White, MD, and associate professor of obstetrics and gynecology at Boston University School of Medicine. […] „Although FVL may seem like a complicated disorder, it’s easy to diagnose. Your doctor can confirm that you have FVL using two blood tests factor V Leiden mutation analysis and Prothrombin 20210.” […] „Patients with factor V Leiden may require medications like blood thinners and more intensive monitoring in pregnancy and preoperatively to reduce the risk of maternal morbidity and mortality,” says Jacobson.

• #50 Factor V Leiden and activated protein C resistance – UpToDate

  https://www.uptodate.com/contents/factor-v-leiden-and-activated-protein-c-resistance

  Factor V Leiden (FVL) results from a point mutation in the F5 gene, which encodes the factor V protein in the coagulation cascade. FVL renders factor V (both the activated and inactive forms) insensitive to the actions of activated protein C (aPC), a natural anticoagulant. As a result, individuals who carry the FVL variant are at increased risk of venous thromboembolism (VTE). However, FVL is very common in the population, and many individuals with the variant will never have a VTE. For these reasons, the ramifications of carrying FVL may present challenging management decisions, both with respect to primary prevention and prevention of recurrent VTE. […] This topic review discusses the diagnosis of FVL and the management of individuals who carry this variant. A brief overview of FVL genetic testing is presented separately. […] Diagnostic tests: – Choice between genetic testing or functional assay – Genetic testing – Functional aPC resistance assays.

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