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Jak2 mutation test negative means Essential BACKGROUND. Clinical Context. . 1849 G>T) mutation results in The type of MPN, complete blood count (CBC) data, and clinical status were correlated with the V617F MAB. Doctors are learning more about genetic changes all the time. , 2005) and suggests that the JAK2 V617F mutation is common in MPD’S as well in hematological disorders, although the occurrence of JAK2 V617F mutation in leukemic patients is less compared to PV and ET (Jones et al. A negative result does not rule out a diagnosis of PV, ET, or PMF. Polycythemia vera (PV) is a stem cell disorder, characterized as a panhyperplastic, malignant, and neoplastic marrow disorder. Abstract. 6% (95% CI 1. When possible, physicians also order molecular tests to identify specific mutations in the bone marrow and blood cells. Clinical significance of the JAK2V617F mutation in patients with a myeloproliferative neoplasm has been the target of intensive research in recent years. * Reference ranges may change over time. JAK2-tree algorithm. In light of the FBE findings, the BCR-ABL1 translocation was searched for via RT-PCR and by FISH for the t(9;22) fusion; both tests were negative. Because the JAK2 blood test is used to detect a specific point mutation of a gene, the test results will either be positive or negative. Each showed no positives in all replicates when assessed with QuanTAS-PCR. given that it includes both patients who ultimately test positive as well as those who ultimately test negative for both BCR-ABL1 and JAK2 V617F. A JAK2 mutation is one of three major diagnostic criteria for polycythemia vera included in the 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia (Blood 2016;127:2391-2405). ||Whole Blood: Do not freeze. The patient was then commenced on Imatinib at 400 mg once daily. The proportion of Explore a comprehensive resource on hematology and oncology, offering insights into various blood disorders and cancer treatments. That can be a secondary disease and possibly curable, whereas polycythemia vera all but requires a mutation in the JAK2 gene, and it is a rare, chronic cancer (manageable, not curable). This Special Article summarizes results from a nationwide laboratory survey of JAK2 and MPL mutation analysis. 1849 G>T) mutation The JAK2 gene is a protein-coding gene of the Janus kinase family. JAK2 V617F mutation is rare in myelodysplastic syndromes and in its presence a myeloproliferative disease needs to be excluded. Chest x-ray and chest CT scan documented subsegmental dysventilation areas in the posterior part A positive JAK2 V617F mutation test means that the person tested is likely to have a myeloproliferative neoplasm (MPN). We chose the HL-60 cell line, given that this cell line (and the Total 256 patients were with elevated Hemoglobin. In a transversal survey Molecular testing of blood or bone marrow is useful in the evaluation of suspected myeloproliferative neoplasms (MPN). JAK2 (V617F) Mutation by ddPCR, Quantitative: >99%. A CT scan of the chest and abdomen was unremarkable, and molecular tests on DNA harvested from whole blood were negative for JAK2 V617F, CALR and MPL gene mutations. It plays a role in cellular signaling. However, response to Imatinib was sub-optimal; thus, JAK2 analysis was requested on the same sample, and it turned out to be positive for the JAK2 mutation (exon14V617F). However, the mutation does not provide additional value in the The percentage of JAK2 positive patients in patients with a score of 1 was 28%. Nature. Workup for suspected hereditary erythrocytosis. gov means it’s official. Correlation and means comparison between V617F MAB and clinical data were analyzed by the Pearson correlation coefficient and t - Test, respectively. 3%) with PV and 66 patients (52. Supportive Data Analytical sensitivity is determined at 0. From them, 391 were tested for JAK2 mutation, and 294 were negative, thus representing our study cohort. The rare mutation V617I is also detected. For those without the JAK2 mutation, the genetic cause was unknown until 2013. The Copenhagen General Population Study, an ongoing population-based prospective cohort study initiated in 2003, served to provide the most robust estimate of JAK2 V617F mutation prevalence to date, 9 and by virtue of accompanying CBC data, has served to support the diagnostic value of JAK2 testing. Lab Test Directory; JAK2 Exon 12 Mutation Analysis by PCR; 2002357. -Positive for JAK2 mutation (other than V617F)-Negative for JAK2 mutations . However, a negative JAK2 V617F result does not indicate absence of an MPN. Allele-specific quantitative PCR (qPCR) is the most prevalent method used in laboratories but with the advent of next-generation sequencing (NGS) techniques, we felt necessary to evaluate this approach for JAK2 mutations testing. Bone marrow samples occasionally used. 8) in the derivation and validation cohorts, respectively. 1-4 Patients positive for V617F had a significantly higher white cell count and neutrophil count than patients negative for V617F, suggesting that the mutation is I've had tests that show my bone marrow is producing too many red blood cells (polycythemia). Positive variant status is highly suggestive of a myeloid neoplasm but must be correlated with clinical and other laboratory features for definitive diagnosis. Deletions in CALR up to 70 bp and insertions up to 12 bp have been detected in validation studies. Repeat testing: In some cases, especially if clinical suspicion for MPN is high despite a negative JAK2 test, repeating the test with a different assay or sending the sample to a reference laboratory can be considered. BCR-ABL Negative Myeloproliferative Disease Cytogenetics The JAK2 V617F mutation is present in approximately 90% of polycythemia vera (PV) cases and approximately 40% of primary myelofibrosis (PMF) or essential The JAK2 gene makes a protein that controls how many blood cells the stem cells make. Brady Stein from Northwestern Medicine explains gene mutations related to MPNs and MPN diagnosis. Direct any questions regarding this test to customer service at 800-345-4363. About 3-4% of people with PV have an exon 12 mutation. This assay has a sensitivity of approximately 1% VAF for JAK2 V617F and 2. 5 Mutations in MPL are seen in approximately 4% of patients with ET and PMF, and mutations in TET2 have been observed in a variety of myeloid malignancies, including JAK2 V617F The JAK2-V617F point mutation is the most frequently detected somatic mutation in the JAK family that leads to constitutive activation of JAK2 and its downstream effectors independent from ligand availability as well as to a hypersensitivity of cytokine receptors upon ligand binding (Figure 2, middle and right schemes) [12,48]. Detection of JAK2 and MPL mutations has been incorporated into routine diagnostic algorithms for these diseases. We value your Feedback. Files of 727,731 patients were screened, and in 4,391 polycythemia was mentioned as a diagnosis on the electronic record. 1-6. This private blood analysis for JAK2 Mutation is accessible at over thirty one private hospitals around the UK. A negative result does not exclude MPNs, as other factors may be involved. Each sample was confirmed to be operationally negative for the JAK2 V617F mutation by testing 10 replicates. 06% (by dilution of a JAK2 V617F-positive cell line DNA into a This is a second-order test that should be used when the test for the JAK2B / JAK2 V617F Mutation Detection, Blood test is negative. The JAK2 protein is a tyrosine kinase and plays important roles in the cell by directing the activity and movement of other proteins. This relentless Diagnostic approach for JAK2 unmutated erythrocytosis. 8% and 100% in A multiplex snapback primer system was developed for the simultaneous detection of JAK2 V617F and MPL W515L/K mutations in Philadelphia chromosome- (Ph-) negative myeloproliferative neoplasms (MPNs). JAK2 (V617F) Mutation by ddPCR, Qualitative: 0. @mgrimes5 has your physician Test Interpretation Analytic Specificity. Although more research is needed to clearly define the role of the JAK2 Abstract. This patient had never been tested for a JAK2 mutation during her earlier chronic myeloid leukemia disease phase. The . The reason for detecting the JAK2 mutation was persistent thrombocytosis or erythrocytosis, failure to respond to treatment, or The test starts with a highly sensitive DNA-based JAK2 V617F test by allele-specific polymerase chain reaction. It is possible to have a negative result and still carry an uncommon CALR mutation that the test cannot detect. MPN is a group of rare conditions that affect the bone marrow The JAK2 V617F Mutation: A Genetic Signature. Classic BCR-ABL1-negative testing, mutant JAK2 V617F allelic burden; MPN JAK2; JAK2 (V617F) Mutation by ddPCR, Qualitative. The JAK2 V617F mutation, a substitution at position 617 in the JAK2 gene, results in a kinase that is perpetually active, akin to a motor that cannot be switched off. 5% VAF for other mutations in JAK2 exons 12 to 15, CALR mutations and MPL mutations. A CALR variant is associated with decreased risk of thrombosis in both ET and PMF and confers a favorable clinical outcome in patients with PMF. The JAK2 Prediction Cohort (JAKPOT) study was conducted at London Health Sciences Centre, a tertiary referral center which serves a population of approximately 2 million in Southwestern Ontario, Canada. CBC data were collected on or near the date of JAK2 V617F MAB testing. 122 patients were excluded in view of meeting one of the exclusion criteria. Around 50 to 60 in 100 people Interpretation. This is because the sequencing technique is required to evaluate for many potential mutations. This exon is important to be studied as almost 3% of PV patients exhibit mutations in jak2 exon 12 12, 13. Specimen Type: Blood: The . Testing is performed on plasma for increased sensitivity whenever possible. A negative result typically means that the CALR mutation being tested for was not detected. People with CALR mutations also have a lower risk of harmful blood clots (thrombosis) than those with JAK2-positive ET. Deletions in JAK2 up to 6 bp and insertions up to 34 bp have been detected in validation studies. Please refer to Mutations in the JAK2, CALR, and MPL genes are considered driver events in the BCR-ABL1 negative myeloproliferative neoplasms (MPN), including polycythemia vera (PV), primary myelofibrosis (PMF) and essential thrombocythemia (ET). 1), which fuses the Janus activated kinase 2 gene (JAK2) with the human autoantigen pericentriolar material gene 1 (PCM1), resulting in a constitutively activated tyrosine kinase ; Observed in both myeloid and lymphoid neoplasms and can present as myeloproliferative neoplasm (MPN), We found the JAK2 V617F mutation present in just more than half of cases of idiopathic myelofibrosis, which accords well with previous estimates of its frequency in this disorder. You came to the right place to seek possible causes of high platelet count with a negative JAK2 test. Of these, polycythemia was confirmed in 1,483 based on laboratory values. Included in every request for JAK2 Mut Recurrent mutations in JAK2 and MPL genes are genetic hallmarks of BCR-ABL1–negative myeloproliferative neoplasms. Additional 58 patients were excluded because of lack of JAK2 mutational analysis. It is possible to have a negative result and still carry an uncommon CALR mutation that the test cannot The germline mutation in S505N, a point mutation that leads to the loss of the inhibitory effect on the TPO genes, was identified in 2 patients in the study cohort and is well recognized in several kindreds. BCR-ABL1 negative testing; Classic BCR-ABL1-negative testing; MPN JAK2; mutant JAK2 V617F allelic burden; JAK2 (V617F) Mutation by ddPCR, Quantitative. Limitations JAK2 V617F Mutation by ddPCR Analysis About Test: This test looks for mutations in JAK2 that are associated with bone marrow disorders caused by the production of too many blood cells. 2%. This Find a Test; JAK2 V617F Mutation JAK2 V617F Mutation « Find Another Test The JAK2 V617F mutation is detectable in approximately 95% PV, 55% ET, and 65% PMF patients. Testing for that gene mutation is a diagnostic tool. The JAK2 mutation test detects mutations in the JAK2 gene, which are associated with myeloproliferative neoplasms (MPNs). A negative JAK2 V617F test but a positive JAK2 exon 12 JAK2 mutation is useful in distinguishing polycythemia vera from secondary causes of erythrocytosis. 15793561. It is known that functionally similar JAK2 exon 12 mutations are involved in activation of erythropoietin signaling pathways. Many mutations in exon 12 of JAK2 gene involved in the pathogenesis of PV have also been described since 2007 10, 11. A The person could have a JAK2-negative MPN or their JAK2 mutation was not detected during testing. The JAK2 V617F mutation occurs in 95-98% of patients with PV, 50% to 60% of patients with PMF and 50% to 60% of patients with the JAK2 gene (exons 12 + 14), including detection of the common JAK2 V617F mutation using extracted DNA from blood or bone marrow specimens. from what I understand, the Jak2 on promethease was an increased link to developing ET or PV if you had a positive Jak2 gene, not the actual V617F or any of the major exons could be wrong though. 8%, RBC 6. The multiplex system comprises two snapback versus limiting primer sets for JAK2 and MPL mutation enrichment and detection, respectively. Linear Use to detect the JAK2 V617F mutation in peripheral blood or bone marrow. The median age at polycythemia A negative JAK2 V617F test but a positive JAK2 exon 12 mutation or other non-V617F mutation test along with supporting clinical signs means it is likely that the person has The test does require the use of radioactive chromium, but the amount of radiation is very small—comparable to the natural radioactivity that a person is exposed to on a long airplane The JAK2 V617F Mutation: A Genetic Signature. 8 mg/dL, hematocrit 58. Due to its significant role in hematopoiesis, Jak2 is a frequent target for mutations in cancer, especially myeloid leukemia, lymphoid leukemia and the myeloproliferative neoplasms (MPN). The percent of false negatives was 2. Le Couédic JP. 5%. Evidence notes connections between this gene and some medical conditions. JAK2V617F mutation screening is indicated for the evaluation of erythrocytosis, thrombocytosis, splanchnic vein thrombosis, and otherwise unexplained BCR-ABL1-negative granulocytosis. , 2005 Among them, 127 patients had the JAK2 V617F mutation, comprising 61 patients (95. 0) and 0 (95% CI 0-2. A positive JAK2 V617F mutation test, along with other supporting clinical signs, means it is likely that the patient tested has an Myeloproliferative Neoplasm (MPN). I know that @shenriq and @mjpm2406 had positive JAK2s but perhaps they can lend some insight on what their physicians tested for prior to finding the mutation. Other tests you might have There's no such thing as triple negative for PV because there's only one known genetic mutation for PV (JAK2). The results will be reported as 1 of the 2 states:-Negative for JAK2 V617F variant-Positive for JAK2 V617F variant. MPNs are diagnosed using physical exams, blood tests and bone marrow biopsies. JAK2 unmutated or non-polycythemia vera (PV) erythrocytosis encompasses both hereditary and acquired conditions. Prognosis: Patients with a JAK2 mutation Please provide indications for JAK2 testing and specimen type. He shares which treatments tend to be effective for both JAK2 negative and JAK2 positive patients and discusses the recent discovery Abstract. Some patients test negative for all 3 mutations; many have rare variants of the myeloproliferative neoplasm driver mutations and others have germline mutations in In all cases being evaluated for JAK2 mutation status, the initial test that should be ordered is JAK2M / JAK2 V617F Mutation Detection, Bone Marrow, a sensitive assay for detection of the mutation. However, if no JAK2 V617F mutation is found, further evaluation of JAK2 may be clinically indicated. The MPNs most commonly associated with JAK2 mutation are: polycythaemia vera (PV), where bone marrow makes too This test will assess for the JAK2 V617F (exon 14) mutation first and will reflex to CALR mutation analysis and MPL mutation analysis if the JAK2 V617F mutation is negative. You might have tests for other gene changes. The JAK2 mutation allows for a distinction between two subtypes of idiopathic myelofibrosis and essential thrombocythemia. 76 patients who met the inclusion criteria of JAK2 negative erythrocytosis with normal EPO and normal PaO2. Few investigators have evaluated the usefulness of the JAK2 V617F mutation for explaining the phenotypic variations and for predicting the risk of major clinical events in primary myelofibrosis (PMF). Jak2 is a non-receptor tyrosine kinase that is involved in the control of cellular growth and proliferation. The relationship between the JAK2V617F mutation and myeloproliferative neoplasms was described in 2005, and has since paved the way for a new understanding If the first blood test suggests you have ET, you might have another blood test to look for a change in a gene called JAK2. Physicians may also Overall, our results confirm previous reports on the prevalence of JAK2 mutations in PV, ET, CML, and MDS (Jones et al. However, there is considerably uncertainty about prognosis in JAK2V617F positive individuals without overt signs of myeloproliferative disease. The use of this Use to detect the JAK2 V617F mutation in peripheral blood or bone marrow. These disorders can include: essential thrombocythemia, polycythaemia vera or primary myelofibrosis. We evaluated whether they met the criteria for the 2016 WHO classification for the included patients . The JAK2 mutation frequency was reported to Variants in JAK2, CALR, and MPL are essentially mutually exclusive. A unique clonal JAK2 mutation leading to constitutive signaling causes polycythaemia vera. This test will assess mutations in JAK2 exons 12, 13, 14 and 15. JAK2V617F is sufficiently prevalent in BCR-ABL1-negative myeloproliferative neoplasms (MPNs) to be useful as a clonal marker. Many patients with BCR/ABL negative myeloproliferative neoplasms carry a JAK2 V617F activating mutation in exon 14. Several reasons suggest that a mutation on the From them, 391 were tested for JAK2 mutation, and 294 were negative, thus representing our study cohort. The JAK2 gene makes a protein that controls how many blood cells the stem cells make. Other important molecular markers in BCR-ABL1-negative MPN include CALR exon 9 variant (20%-30% of PMF and ET) and MPL exon 10 variant (5%-10% of For those with the JAK2 mutation, this is likely the specific genetic basis for their ET diagnosis. which means that assays are performed multiple times during the day. THE STORY OF JAK2 Four teams race to find the mysterious cause of a group of blood cancers. The JAK2 mutation test may be used, along with other tests such as erythropoietin, to help diagnose bone marrow disorders that lead to overproduction of blood cells. Transport 3 mL bone marrow. Detection of the JAK2 V617F variant is useful to help establish the diagnosis of MPN. Limit of Detection. In this study, we tested the hypothesis that increased JAK2V617F If the JAK2 V617F and BCR-ABL assays are negative, CALR and MPL mutation assays should be done. JAK2 MUTATIONS AT A GLANCE Involved in: blood cancers and disorders including polycythemia vera, primary myelofibrosis, thrombocythemia, leukemia. PCM1-JAK2 fusion is a rare genomic abnormality resulting from t(8;9)(p22;p24. 21 Four of 10 patients A test for the JAK2 V617F/12 exon mutation was performed, with negative result, after an incidental finding of erythrocytosis (Hb 19. It has also been detected in subsets of each of the other Ph-negative MPDs; in 23–57% of ET and 43–67% of IMF patients, as well as in some Ph-negative CML and MDS. These conditions are known as myeloproliferative neoplasms (MPNs). However, if the JAK2 mutation test is negative, one is no further along the road away from agnosticism. Kralovics R, Passamonti F, Buser AS, et al People with CALR mutations also have a lower risk of harmful blood clots than those with JAK2-positive ET. In those without JAK2, MPL, or CALR mutations (triple-negative MPNs), a next generation sequencing (NGS) myeloid panel can be useful to establish clonality. JAK2-tree validation using population data. A fault with your JAK2 gene means the stem cells can start producing red blood cells when they're not meant to. (Min: 1 mL)Bone Marrow: Do not freeze. JAK2 V617F, if present in peripheral blood, may provide valuable diagnostic information in this setting, allowing more confident initiation of appropriate cytoreductive therapy with hydroxyurea or anagrelide. An accurate clinical history and physical examination accompanied Even though JAK2 mutations are found in the vast majority of PV patients, “true” PV has been described in patients lacking mutations in the exon 12 or 14 of JAK2, raising the question of other mutations causing this phenotype. 6%. 9 × 10 6) after the patient had been living at high altitude (about 3000 meters). A triple negative (JAK2 V617F, CALR, and MPL-negative) genotype is considered a high-risk molecular signature in PMF. The JAK2 V617F mutation is associated with myeloproliferative neoplasms, including polycythemia vera, essential thrombocythemia and primary myelofibrosis. 2005 Apr 28; 434(7037):1144-1148. This test will assess for the JAK2 V617F (exon 14) mutation first and will reflex JAK2 exon 12 to 15 mutation analysis if the JAK2 V617F mutation is negative. A Rational Approach to JAK2 Mutation Testing in Patients with Elevated Hemoglobin: Results from the JAK2 Prediction Cohort (JAKPOT) Study and negative predictive values of 98. In recent years, JAK2 mutation has been a major criterion for CMDs and facilitated the differential diagnosis. 75 patients were males, mean age was 40 Mutation like JAK2, which is seen in BCR-ABL1 negative MPN is usually absent in CML. The revision includes new criteria for diagnosing MPNs by the three main driver mutations in JAK2, CALR, and MPL genes. All adult patients referred for elevated hemoglobin (≥160 g/L for females, or ≥165 g/L for males) between January 1, 2015, and May 12, 2021, who underwent JAK2 mutation If the JAK2 V617F mutation is not detected, testing for CALR and MPL mutations should follow in patients with ET or PMF and JAK2 exon 12 mutations in patients with PV. JAK2 Exon 12 Mutation Analysis by PCR A diagnosis of polycythemia vera (PV) is made following various assessments including hemoglobin (Hb) and hematocrit (HCT) levels, red cell mass (RCM) isotopic measurement, bone marrow biopsy histology, JAK2 mutation, serum JAK2 in the Clinic. The JAK2 V617F mutation is part of the major criteria for diagnosis of myeloproliferative neoplasms (MPN). Figure 1. A fault with your JAK2 gene means the stem cells can start producing platelets when they're not meant to. JAK2 (V617F) Mutation by ddPCR, Qualitative: >99%. Other important molecular markers in BCR-ABL1-negative MPN include CALR exon 9 variant (20%-30% of PMF and ET) and MPL exon 10 variant (5%-10% of The test turned out positive for BCR-ABL1 (e14a2/e13a2) 61. Transport 5 mL whole blood. a JAK2 V617F mutation-negative cell line was required. JAK2 V617F Mutation Analysis - This DNA-based assay tests leukocytes from blood or bone marrow aspirate for mutation at codon 617 of JAK2, using an advanced DNA sequencing method. 19–21 The phenotype of V617F-positive, Most appropriate in cases of high suspicion of polycythemia vera with negative JAK2 V617F mutation status. But what if you’re JAK2 negative? Dr. The JAK2 V617F mutation has been reported in 95% of patients with polycythemia vera On the other side, the causes of reactive thrombocytosis, such as iron deficiency anemia and autoimmune diseases, are more common in the middle-aged women and also JAK2 mutation is negative. Polycythemia vera is characterized by the presence of a JAK2 mutation. 8%) with ET. JAK2 (V617F) Mutation by ddPCR, Quantitative: 0. Reference Range * Interpretive report provided. A subnormal serum EPO level is suspicious for the presence of an EPOR mutation, as illustrated in Case 1. A negative test means that the bothersome physical symptoms being experienced, such as unusual fatigue, Hi @mgrimes5, I's like to welcome you to Mayo Clinic Connect. Hereditary erythrocytosis is suspected in children and young adults with long-standing erythrocytosis, particularly with a positive family history [83, 84]. Therefore, their screening is A negative JAK2 V617F test but a positive JAK2 exon 12 mutation or other non-V617F mutation test along with supporting clinical signs means it is likely that the person has polycythemia vera. The other study populations are narrower Detection of the JAK2 V617F variant is useful to help establish the diagnosis of MPN. However, in the MPN known as ET (essential thrombocythemia), there are 3 genetic mutations (JAK2, CalR and MPL) and people who are found by bone marrow biopsy to have ET but none of the above mutations are "triple negative". JAK2 mutations are diverse and JAK2 variant mutations may lead to a myelodysplastic syndrome phenotype. Other tests. Many people with ET have a mutation in a gene called Jak2 Mutation is tested to determine/diagnose bone marrow disorders. Testing requires: a blood draw. This test is a second-order test that should be ordered when the test for Test JAK2 Mutation; Common Abbreviations: Profile: Clinical Indication: The JAK2 mutation test may be used, along with other tests such as erythropoietin, to help diagnose bone marrow disorders that lead to overproduction of blood cells. JAK2 R564L and JAK2 I670V are reported as JAK2 mutation variants in association with a myelodysplastic phenotype. A systematic diagnostic approach begins with documentation of historical hematocrit This case report focuses on a 71-year old patient affected by unknown dyspnea and erythrocytosis referred by his general practitioner to our center for specialist advice after a hematological examination had excluded polycythemia vera on grounds of negative test for JAK2 V617F/exon 12 mutation. Patients with JAK2 V617F-negative MPN or JAK2 V617F-positive PMF were excluded. What does the result mean? If the JAK2 V617F mutation is detected and the JAK2 exon 12 and other exon mutations occur mostly in patients with JAK2V617F-negative polycythemia vera, and they are almost always associated with subnormal serum erythropoietin level. Molecular testing of blood or bone marrow is useful in the evaluation of suspected myeloproliferative neoplasms (MPN). This relentless The JAK2 exon 12 test may be ordered when the JAK2 V617F test is negative and the doctor still suspects PV. The JAK2 (Janus kinase 2) gene encodes for a non-receptor protein tyrosine kinase that activates cytokine and growth factor signaling. The V617F (c. The JAK2 tests are performed on the genetic material found in granulocytes (from blood or bone marrow) and red cell precursors (from bone marrow), but not all granulocytes and red cell precursors will possess the JAK2 mutations. The JAK2 (Janus kinase 2) gene encodes for a non-receptor protein tyrosine kinase that In rare cases, a mutation other than JAK2 V617F may be present in an area that interferes with primer or probe binding and cause a false-negative result. The sensitivity of this assay is much less than that of the JAK2B test. rngf zupxjjjv kzkd xatak bspzt wrnvkk lkyaiu bbagnbd jypfrb yojw