The role of a low erythropoietin level for the polycythemia vera diagnosis

The 50th anniversary of Blood Cells, Molecules and Diseases, 1975-2024

The journal Blood Cells was initiated in 1975 by Marcel Bessis, a French hematologist and cell biologist, as a vehicle for the publication of papers and discussions presented at an international blood club meeting he convened at L' Institut de Pathologie Cellulaire on the campus of Hôpital Bicétre in Kremlin Bicétre, France, a commune on the southern border of Paris. The group met at the Institute for the first time in October 1972. After the first meeting, Bessis published the articles describing the presentations in the Nouvelle Revue d'Hématologie Française, France's principal journal for articles on the science and practice of hematology of which he was the editor. The refusal of the Nouvelle Revue d'Hématologie Française to continue publishing the papers from the meeting of the blood club in English prompted Bessis to start a new journal, Blood Cells, in 1975. Blood Cells, also, began to accept individual submitted papers unrelated to the blood club meeting and, thus, it evolved into a standard journal. A decade later, when Bessis became ill, he asked Brian Bull, a hematopathologist and professor at Loma Linda University School of Medicine in California to assume the position as the second editor-in-chief. He and Bessis had become scientific collaborators and good friends in the preceding years. In 1995, Ernest Beutler, Chair of Molecular and Experimental Medicine at Scripps Research Institute, assumed the editor-in-chief position and transformed the Journal by making three consequential changes. He expanded its title to Blood Cells, Molecules and Diseases, converted its editorial board to past presidents of the American Society of Hematology plus a few additional experimental hematologists of note, a few from abroad, and he converted the Journal to a digital format, hosted on the Scripps Research Institute server. The Journal was the first published solely in a digital format. It, subsequently, was bought by Academic Press, then Harcourt and, then, by Elsevier. The next three editors-in-chief were (i) Marshall A. Lichtman, then Professor of Medicine (Hematology) and of Biochemistry and Biophysics and former Dean of the School of Medicine and Dentistry at the University of Rochester Medical Center, editor from 2000 to 2013, (ii) Mohandas Narla, then Vice President for Research and Director of The Laboratory of Red Cell Physiology at the New York Blood Center, editor from 2014 to 2021 and (iii) Lionel Blanc, Professor of Molecular Medicine and Pediatrics, Center for Autoimmune, Musculoskeletal and Hematopoietic Diseases, Institute of Molecular Medicine, The Feinstein Institutes for Medical Research and the Les Nelkin Professor of Pediatric Oncology Donald and Barbara Zucker School of Medicine at Hofstra-Northwell from 2022 to the present. Although the Journal publishes papers on any aspect of hematology, it has developed a focus on disorders of red cells, erythropoiesis and hematopoiesis. In October 2024, it celebrates its 50th anniversary as a vehicle for the publication of papers in the discipline of hematology.

Diagnostic Approaches to Investigate JAK2-Unmutated Erythrocytosis Based on a Single Tertiary Center Experience

INTRODUCTION

Erythrocytosis is attributed to various clinical and molecular factors. Many cases of JAK2-unmutated erythrocytosis remain undiagnosed. We investigated the characteristics and causes of JAK2-unmutated erythrocytosis.

METHODS

We assessed the clinical and laboratory results of patients with erythrocytosis without JAK2 mutations and performed targeted next-generation sequencing (NGS) panels for somatic and germline mutations.

RESULTS

In total, 117 patients with JAK2-unmutated erythrocytosis were included. The median hemoglobin and hematocrit levels were 17.9 g/dL and 53.4%, respectively. Erythropoietin levels were not below the reference range. Thrombotic events were reported in 17 patients (14.5%). Among JAK2-unmutated patients, 44 had undergone targeted panel sequencing consisting of myeloid neoplasm-related genes, and 16 had one or more reportable variants in ASXL1 (5/44), TET2, CALR, FLT3, and SH2B3 (2/44). Additional testing for germline causes revealed eight variants in seven genes in eight patients, including NF1, BPGM, EPAS1, PIEZO1, RHAG, SH2B3, and VHL genes. One NF1 pathogenic, one BPGM likely pathogenic, and six variants of undetermined significance were detected.

CONCLUSION

Somatic and germline mutations were identified in 36.4% and 33.3 % of the JAK2-unmutated group; most variants had unknown clinical significance. Not all genetic causes have been identified; comprehensive diagnostic approaches are crucial for identifying the cause of erythrocytosis.

Erythrocytosis: Diagnosis and investigation

An absolute erythrocytosis is present when the red cell mass is greater than 125% of the predicted. This is suspected when the hemoglobin or hematocrit is above the normal range. An erythrocytosis can be classified as primary or secondary and congenital or acquired. The commonest primary acquired disorder is polycythemia vera. The diagnostic criteria for PV have evolved over time and this is the main diagnosis managed in hematology clinics. There are a variety of rare congenital causes both primary and secondary. In particular in young patients and/or those with a family history a congenital cause is suspected. There remains a larger cohort with acquired erythrocytosis mainly with non-hematological pathology. In order to explore for a cause of erythrocytosis, measurement of the erythropoietin level is a first step. A low erythropoietin level indicates a primary cause and a normal or elevated level indicates a secondary etiology. Further investigation is then dictated by initial findings and includes mutational testing with PCR and NGS for those in whom a congenital cause is suspected. Following this possibly bone marrow biopsy, scans, and further investigation as indicated by history and initial findings. Investigation is directed toward the identification of those with a hematological disorder which would be best managed following guidelines in hematology clinics and referral elsewhere in those for whom there are non-hematological reasons for the elevated hemoglobin.

The Systemic Inflammation Index: A New Candidate Minor Criterion in the Diagnosis of Polycythemia Vera

AIM

To investigate inflammation indices and erythropoietin levels for their potential role in distinguishing polycythemia vera from secondary polycythemia and to compare different parameter combinations in terms of the diagnostic accuracy.

METHODS

This retrospective cohort was created from patients assessed for polycythemia from January 2020 to December 2023. Polycythemia vera diagnosis was made according to the 2016 World Health Organization criteria (n = 145). Those who did not fulfill the criteria were defined as having secondary polycythemia (n = 84).

RESULTS

The neutrophil lymphocyte ratio, platelet lymphocyte ratio and systemic immune-inflammation index were significantly higher in the polycythemia vera group (p < 0.001 for all). Erythropoietin had the highest area under the curve in the analysis to distinguish groups, followed by the systemic immune-inflammation index. The platelet lymphocyte ratio (≥135) had the highest specificity to detect polycythemia vera, followed closely by the systemic immune-inflammation index. The sensitivity for polycythemia vera detection was highest with the erythropoietin and systemic immune-inflammation index combination, followed by erythropoietin and the neutrophil lymphocyte ratio. All the single and combinatory variables exhibited significant performance in predicting polycythemia vera after adjusting for age and sex. However, the erythropoietin and systemic immune-inflammation index combination had the highest odds ratio, followed by erythropoietin alone.

CONCLUSION

These are promising findings supporting the usability of these biomarkers, especially the systemic immune-inflammation index, as minor criteria in the diagnosis of polycythemia vera. It is especially crucial to note that using erythropoietin in combination with these markers may improve diagnostic accuracy.

Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio as new possible minor criteria for diagnosis of polycythemia vera

INTRODUCTION

The role of inflammation in the pathophysiology of polycythemia vera (PV) is important. The presence of JAK2 mutations is important in the diagnosis of PV, and serum levels of erythropoietin (EPO) also play a supporting role. However, serum EPO levels show some limitations. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are a readily available marker of inflammation. Thus, we examined whether NLR & PLR might diagnose PV in erythrocytosis patients. We compared NLR & PLR and EPO diagnostic values.

METHODS

We retrospectively reviewed clinical and laboratory data from two referral hospitals. Two hundred and eighty-five patients with erythrocytosis who underwent a test for the JAK2 mutation were included. It wac classified as the PV group and the secondary polycythemia (SP) group.

RESULTS

The median NLR & PLR in the PV group (n = 70) was significantly higher than that in the SP group (n = 170) (NLR: 6.04 vs. 1.77, PLR: 283.18 vs. 101.56, respectively, p < 0.001). In the receiver operating characteristic analysis, the area under the curve of NLR & PLR was significantly higher than that of serum EPO (NLR vs EPO: 0.921 vs. 0.827, p = 0.003; PLR vs EPO: 0.917 vs 0.827, p = 0.003).

CONCLUSION

In conclusion, NLR & PLR were higher in PV than in SP and showed better diagnostic value than serum EPO level, highlighting their potential as minor diagnostic criteria in patients with PV.

The utility of testing erythropoietin level in polycythemia diagnosis

OBJECTIVES

Polycythemia vera (PV) is classically thought to be associated with low erythropoietin (EPO) levels. Here, we present a review of the utility of using EPO levels in diagnosing polycythemia.

METHODS

We conducted a systematic literature review of the Medline data through Pubmed and Google Scholar. We included the articles which described confirmed PV associated with elevated EPO level. Our search strategy included the following terms in Pubmed (((polycythemia vera[MeSH Terms]) OR (jak2 protein tyrosine kinase[MeSH Terms])) OR (Myeloproliferative Disorders[MeSH Terms])) AND (Erythropoietin[MeSH Terms]), and 'polycythemia vera with erythropoietin' in Google Scholar.

RESULTS

Our research yielded four cases of PV with elevated EPO levels. The most common symptom was a headache. Thrombotic phenomena happened in a single case in the form of Budd-Chiari syndrome. The mean Hb level was 20.2 gm/dl, and the EPO level was 213 mlU/mL.

DISCUSSION

Although PV is usually associated with low EPO levels, high levels do not exclude this diagnosis. Workup should include testing for JAK2 mutation and bone marrow biopsy in the presence of suggestive signs and symptoms. Novel biomarkers are also being proposed to aid in the diagnosis.

CONCLUSION

Although elevated EPO levels suggest secondary causes of polycythemia, cases where elevated EPO levels were associated with an underlying PV are reported in the literature, and we have summarized a review of them. Workup for polycythemia should include JAK2 mutation testing if signs and symptoms suggest PV even if EPO is elevated.

Management of classical Philadelphia chromosome-negative myeloproliferative neoplasms in Asia: consensus of the Asian Myeloid Working Group

Myeloproliferative neoplasms (MPN) are a heterogeneous group of clonal hematopoietic stem cell disorders characterized clinically by the proliferation of one or more hematopoietic lineage(s). The classical Philadelphia-chromosome (Ph)-negative MPNs include polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). The Asian Myeloid Working Group (AMWG) comprises representatives from fifteen Asian centers experienced in the management of MPN. This consensus from the AMWG aims to review the current evidence in the risk stratification and treatment of Ph-negative MPN, to identify management gaps for future improvement, and to offer pragmatic approaches for treatment commensurate with different levels of resources, drug availabilities and reimbursement policies in its constituent regions. The management of MPN should be patient-specific and based on accurate diagnostic and prognostic tools. In patients with PV, ET and early/prefibrotic PMF, symptoms and risk stratification will guide the need for early cytoreduction. In younger patients requiring cytoreduction and in those experiencing resistance or intolerance to hydroxyurea, recombinant interferon-α preparations (pegylated interferon-α 2A or ropeginterferon-α 2b) should be considered. In myelofibrosis, continuous risk assessment and symptom burden assessment are essential in guiding treatment selection. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) in MF should always be based on accurate risk stratification for disease-risk and post-HSCT outcome. Management of classical Ph-negative MPN entails accurate diagnosis, cytogenetic and molecular evaluation, risk stratification, and treatment strategies that are outcome-oriented (curative, disease modification, improvement of quality-of-life).

Contribution of lowered hemoglobin threshold value in the diagnosis of polycythemia vera: Comparison of 2016 and 2008 WHO criteria

Polycythemia vera (PV) diagnosis remains a difficult task despite various updates in the 2016 World Health Organization (WHO) diagnostic criteria compared to 2008 criteria. This study aimed to examine the biochemical and clinical features of patients diagnosed with PV using the WHO 2016 criteria but would have been missed by the WHO 2008 criteria, and to ascertain the impact of the lowered thresholds on PV diagnosis. A total of 229 patients with suspected myeloproliferative neoplasms were included in this cross sectional study. The study group was divided with regard to hemoglobin values. Group A consisted of 126 patients with hemoglobin values of ≤ 18.5 g/dL in males and ≤ 16.5 g/dL in females. Group B comprised 103 patients with hemoglobin values of > 18.5 g/dL in males and > 16.5 g/dL in females. The number of PV diagnoses increased to 145 from 87 (increased by 66.67%) when the 2016 diagnostic criteria were employed rather that the 2008 criteria. Mean age and the frequency of female subjects were lower in Group A compared to Group B. The groups were similar in terms of chronic obstructive pulmonary disease/obstructive sleep apnea syndrome, spleen status, smoking status, and mean corpuscular volume, white blood count, neutrophil, eosinophil and platelet values. red blood cells and lactate dehydrogenase values were significantly higher, while lymphocyte counts were significantly lower in Group B. With the introduction of WHO 2016 criteria, we found a significant increase in the number of patients who were candidates for PV testing and were ultimately diagnosed with PV. These findings support the diagnostic value of the 2016 WHO criteria, and by extension, the lowered thresholds for detection of patients requiring further analysis.

Analysis of JAK2V617F Tyrosine Kinase Mutation in Blood Donors with Erythrocytosis - A Pilot Study in a Tertiary Care Teaching Hospital of South India

Purpose

Transfusion services and blood centers provide immediate medical evaluation to blood donors by physical examination and hemoglobin (Hb) screening. Screening for Hb value before every blood donation is mainly aimed to rule out anemia. However, it is not uncommon to defer the donors for high Hb value which can be due to primary or secondary polycythemia. This study aimed to analyze the frequency of JAK2V617F mutation among blood donors with a high Hb of >18 g/dl.

Patients and Methods

A prospective study was conducted over a period of 18 months involving blood donors with a persistently high Hb value of >18 g/dl. Complete blood count (CBC), JAK2V617F gene mutation and Serum Erythropoietin (EPO) levels in study donors were analyzed. Descriptive statistical analysis was performed using SPSS, version 24 (IBM, USA).

Results

Of 13,798 screened donors, 48 donors (0.34%) had persistent erythrocytosis with a high Hb value of >18 g/dl. Their age ranged between 20-50 years with a mean of 31.2 ± 6.66. The CBC parameters including red blood cell (RBC) count, Hb%, hematocrit (Hct), white blood cell (WBC) count and the platelet count ranged from 4.35-8.43 million/µL (6.2 ± 0.6), 18.6-24.4 g/dl (19 ± 0.94), 51.9-83.3% (58 ± 5.02), 3.99-10.8 × 103/µL (7.8 ± 1.5), and 120-450 × 103/µL (227 ± 57.2), respectively. Estimated mean EPO value was 8.29 mIU/± 0.04. JAK2V617F mutation was detected in 2 donors (4.1%).

Conclusion

The prevalence of persistent erythrocytosis among blood donors was 0.34% and among them, two donors (4.1%) harbored the JAK2V617F mutation. Thus, blood centers play an important role in the primary screening of donors with high hemoglobin leading to early detection and management of polycythemia vera (PV).

Clinical features of acquired erythrocytosis: Low levels of serum erythropoietin in a subset of non-neoplastic erythrocytosis patients

BACKGROUND

Acquired erythrocytosis can be classified into polycythemia vera (PV) and non-neoplastic erythrocytosis (NNE). The vast majority of PV patients harbor JAK2 mutations, but differentiating JAK2 mutation-negative PV from NNE is challenging due to a lack of definitive molecular markers.

METHODS

We studied the clinical features of 121 patients with erythrocytosis of which 47 (38.8%) were JAK2 mutation-positive and also fulfilled the diagnostic criteria for PV, and 67 (55.4%) JAK2 mutation-negative erythrocytosis patients who were diagnosed as NNE. Diagnosis was strictly based on driver mutation analysis and central pathology review.

RESULTS

No JAK2 mutation-negative PV patients were found in our cohort. The NNE group showed significantly younger (p < 0.01) age with higher frequency of smoking (p < 0.001), alcohol consumption (p < 0.001), and diabetes mellitus (p < 0.05), whereas the PV group (n = 47) showed significantly higher white blood cell count, platelet count, and lactate dehydrogenase (p < 0.001). Although serum erythropoietin (EPO) levels were significantly higher in NNE compared to PV (p < 0.001), approximately 40% of the NNE patients had EPO levels below the lower range of normal, fulfilling a minor diagnostic criterion of PV and raising the possibility of PV misdiagnosis.

CONCLUSION

Low EPO levels in JAK2 mutation-negative erythrocytosis may not be a reliable diagnostic criterion for distinguishing PV from NNE.

Erythroid lineage Jak2V617F expression promotes atherosclerosis through erythrophagocytosis and macrophage ferroptosis

Elevated hematocrit is associated with cardiovascular risk; however, the causality and mechanisms are unclear. The JAK2^V617F (Jak2^VF) mutation increases cardiovascular risk in myeloproliferative disorders and in clonal hematopoiesis. Jak2^VF mice with elevated WBCs, platelets, and RBCs display accelerated atherosclerosis and macrophage erythrophagocytosis. To investigate whether selective erythroid Jak2^VF expression promotes atherosclerosis, we developed hyperlipidemic erythropoietin receptor Cre mice that express Jak2^VF in the erythroid lineage (VFEpoR mice). VFEpoR mice without elevated blood cell counts showed increased atherosclerotic plaque necrosis, erythrophagocytosis, and ferroptosis. Selective induction of erythrocytosis with low-dose erythropoietin further exacerbated atherosclerosis with prominent ferroptosis, lipid peroxidation, and endothelial damage. VFEpoR RBCs had reduced antioxidant defenses and increased lipid hydroperoxides. Phagocytosis of human or murine WT or JAK2^VF RBCs by WT macrophages induced ferroptosis, which was prevented by the ferroptosis inhibitor liproxstatin-1. Liproxstatin-1 reversed increased atherosclerosis, lipid peroxidation, ferroptosis, and endothelial damage in VFEpoR mice and in Jak2^VF chimeric mice simulating clonal hematopoiesis, but had no impact in controls. Erythroid lineage Jak2^VF expression led to qualitative and quantitative defects in RBCs that exacerbated atherosclerosis. Phagocytosis of RBCs by plaque macrophages promoted ferroptosis, suggesting a therapeutic target for reducing RBC-mediated cardiovascular risk.

Is high hemoglobin a hindrance factor for blood donation? A pilot observational study from the coastal region of India

BACKGROUND

Blood donors with high Hb are often deferred for the presumed risk of polycythemia vera (PV). However, adequate data to substantiate or refute this hypothesis is lacking.

METHODOLOGY

We conducted an observational study on blood donors found to have high hemoglobin (Hb≥18g/dL) during the pre-donation screening process using a portable hemoglobinometer at our blood center for four months. We adopted a cost effective methodology wherein a questionnaire was used to elicit the secondary causative factors of high hemoglobin and a complete blood count test to observe the blood cell parameters and JAK2V617F mutation test was performed in a subset of donors lacking secondary erythrocytosis (SE) history.

RESULTS

Of the total 7076 donors enrolled, 112 male donors (1.58%) had high hemoglobin. The majority (70.4%) were repeat donors with mean age of 31.4 years. About 61% of the donors had attributable factors for SE like smoking, occupational exposure to carbon monoxide. The mean hemoglobin value of capillary and venous hemoglobin demonstrated a statistically significant difference (P<0.05) where 2.7% of donors had venous Hb<18g/dL. The hematological profile of all the donors showed increased RBC but normal platelet and WBC count. Of 24 donors included for the JAK2V617F test, none had a positive report.

CONCLUSION

This study suggests high hemoglobin in blood donors is less likely due to PV. Hence, re-considering their deferral may help alleviate donor anxiety and allow donor return. However, multi-centric studies are required to develop consensus statements on PV risk status and blood donation eligibility.

Polycythemia Rubra Vera and Sporadic Bilateral Renal Angiomyolipomas: A Case Report

Polycythemia rubra vera (PRV) is a clonal myeloproliferative neoplasm characterized by autonomous production of erythrocytes, neutrophils, and platelets. Angiomyolipomas (AMLs) are benign renal perivascular epithelioid cell neoplasms of which approximately 80% are sporadic. Here, we report synchronous diagnoses of PRV and asymptomatic sporadic bilateral renal AMLs in a 71-year-old woman. We describe her treatment with phlebotomy and hydroxyurea for PRV and surveillance for renal AMLs. We compare the features and treatment of the present case with those of two previously reported women who also had PRV and sporadic renal AMLs. Finally, we discuss the management and acquired genetic basis of both neoplasms.

High platelet-to-lymphocyte ratio may differentiate polycythemia vera from secondary polycythemia

Discriminating polycythemia vera (PV) from secondary polycythemia (SP) is crucial due to the inherent risk of thrombosis in PV and different treatment approaches. The majority of PV patients have subnormal serum erythropoietin levels and harbor Janus kinase 2 (JAK2) mutations; however, serum erythropoietin levels may be normal in approximately one third of PV patients and mutational analysis is costly and requires access to specialized laboratories. Recently, neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte ratios (PLR) emerged as rapidly available biomarkers to identify PV patients under an increased risk of thrombosis and death. This multicenter retrospective study investigated whether these two biomarkers may also be used to differentiate PV from SP. A total of 207 subjects were included (103 PV and 104 SP) with both baseline NLR (median 4.33 vs. 1.89) and PLR (median 259.12 vs. 81.11) being significantly higher in PV than in SP (p < 0.001 for both analyses). According to the receiver operating curve analysis, PLR (area under the curve, AUC 0.936, the optimal cut-off value of > 138.1 had 82.5% sensitivity and 91.67% specificity for the detection of PV) outperformed other tested variables (NLR, total leukocytes, neutrophils, lymphocytes and platelets) and its cut-off values with 100% specificity and sensitivity were able to confirm (PLR > 224.56; 31% patients) and to exclude (PLR < 68.8; 13% patients) the highest proportions of PV patients. Therefore, PLR may represent a cheap and a rapidly available biomarker with valuable diagnostic and prognostic properties. This information may be particularly useful in resource-limited settings; however, our results need validation on larger datasets.

Revisiting Diagnostic performances of serum erythropoïetin level and JAK2 mutation for polycythemias: analysis of a cohort of 1090 patients with red cell mass measurement

We assessed the diagnostic performances of erythropoietin and JAK2 mutations in 1,090 patients with suspected polycythemia who were referred for red cell mass (RCM) measurement. In patients with a high haematocrit and/or haemoglobin level, a low erythropoietin level (<=3·3 mUI/ml) and JAK2 mutation showed comparable positive predictive value (PPV) for true polycythemia (RCM>=125%), 92·1% and 90% respectively. A very-low erythropoietin level (<=1·99 mUI/ml) had a PPV of 100% for polycythemia vera (PV) diagnosis. We confirmed the correlations between RCM, erythropoietin and JAK2 variant allelic frequency in PV patients. This study prompts the need to revisit the role of EPO in PV diagnostic criteria.

Diagnostic Performance of Erythropoietin Levels in Polycythemia Vera: Experience at a Comprehensive Cancer Center

INTRODUCTION

Considering the evolving diagnostic criteria of polycythemia vera (PV), we analyzed the utility of serum erythropoietin (EPO) as a predictive marker for differentiating polycythemia vera (PV) from other etiologies of erythrocytosis.

PATIENTS AND METHODS

We conducted a retrospective study after a review of electronical medical records from January 2005 to December 2016 with diagnosis of erythrocytosis using International Classification of Disease-specific codes. To evaluate the diagnostic performance of EPO levels and JAK2-V617F mutation, we constructed a receiver-operated characteristic curve of sensitivity versus 1-specificity for serum EPO levels and JAK2-V617F mutation as predictive markers for differentiating PV from other causes of erythrocytosis.

RESULTS

We surveyed 577 patients with erythrocytosis. Median patient age was 59.2 years, 57.72% (n = 329) were male, 86.3% (n = 491) were white, and only 3.3% (n = 19) were African American. A total of 80.88% (n = 351) of those diagnosed with PV had a JAK2-V617F mutation compared to only 1.47% (n = 2) whose primary diagnosis was secondary polycythemia. When comparing JAK2-V617 mutation to the EPO level, the area under the curve of JAK2-V617 (0.8970) was statistically larger than that of EPO test (0.6765). Therefore, the PV diagnostic methodology using JAK2-V617 is better than the EPO test. An EPO level of < 2 mIU/mL was > 99% specific to predict PV but was only 12% sensitive.

CONCLUSION

In the appropriate clinical setting, cytogenetic and molecular studies such as JAK2 mutation status prevail as the most useful tools for PV case identification. The use of isolated EPO to screen patients with erythrocytosis is not a good diagnostic approach.