Low erythropoietin (EPO) level may have only moderate predictive accuracy for polycythemia vera (PV), according to study results published in Blood Cells, Molecules and Diseases.

Low EPO level can be used to diagnose PV, but there has been debate over its diagnostic value in light of the increasing availability of advanced molecular testing. The researchers assessed the role of low EPO level for PV diagnosis in the context of positive JAK2 mutation status as well as other diagnostic parameters.

In this retrospective review, 138 patients were enrolled, including 75 patients with PV and 63 with secondary erythrocytosis. Among the 75 patients with PV, 24 had EPO levels within the normal range and 51 had EPO levels below the lower limit. EPO levels were positively correlated with body mass index and smoking status, which the authors noted “[makes] it an unreliable diagnostic marker in these patients.” 

Low EPO level as a standalone diagnostic modality was significantly associated with PV (odds ratio [OR], 0.857; P <.001). However, upon including JAK2V617F mutation status in the prediction model, this association lost statistical significance (OR, 0.962; P =.269). Conversely, 

JAK2V617F positivity alone was found to have strong predictive value for diagnosing PV (P =.006), either alone or in combination with other variables. 

“Using a lower than normal EPO level can lead to underdiagnoses of PV, especially in cases when hemoglobin or hematocrit levels are borderline elevated and patients have a secondary condition that is driving EPO levels to rise,” wrote the researchers. 

They urged clinicians to address diagnostic bias and place a greater emphasis on cytogenetic and molecular studies for the creation of more objective diagnostic criteria. 

Reference

  • Lupak O, Han X, Xie P, et al. The role of a low erythropoietin level for the polycythemia vera diagnosis [published online September 7, 2019]. Blood Cells Mol Dis. doi:10.1016/j.bcmd.2019.102355