Sandes A F, Gonçalves M V, Chauffaille M de L
Division of Hematology, Fleury Group, São Paulo, Brazil.
Int J Lab Hematol. 2017 Oct;39(5):528-531. doi: 10.1111/ijlh.12686. Epub 2017 May 12.
Polycythemia vera (PV) is a disorder characterized by clonal proliferation of myeloid cells and increased red blood cell mass. Recently, the revised 2016 WHO classification of myeloid neoplasms decreased the threshold levels of hemoglobin and hematocrit for the diagnosis of PV. However, the new proposed cutoffs have remarkable overlap with the normal reference values reported and the clinical impact of these new cutoffs has not been widely assessed in the general population.
We retrospectively examined 248 839 patients with presumptively normal complete blood cell results, consecutively obtained in an outpatient setting.
The proportion of men with Hb >165 g/L was 5.99%, Hct>49% was 2.4%, and Hb >165 g/dL or Hct>49% was 6.48%, while the proportion of women with Hb >160 g/L was 0.22%, Hct>48% was 0.11%, and Hb >160 g/L or Hct>48% was 0.28%.
The isolated use of the proposed Hb/Hct levels as a definer of polycythemia may lead to a substantial increase in unnecessary diagnostic tests. In cases with borderline levels of hemoglobin, the diagnostic workup of PV should only be indicated in the presence of clinical and/or laboratorial features associated with MPN.
真性红细胞增多症（PV）是一种以髓系细胞克隆性增殖和红细胞量增加为特征的疾病。最近，2016年世界卫生组织（WHO）修订的髓系肿瘤分类降低了PV诊断时血红蛋白和血细胞比容的阈值水平。然而，新提出的临界值与所报道的正常参考值有显著重叠，并且这些新临界值对普通人群的临床影响尚未得到广泛评估。
我们回顾性研究了在门诊连续获得的248839例假定全血细胞结果正常的患者。
血红蛋白>165g/L的男性比例为5.99%，血细胞比容>49%的为2.4%，血红蛋白>165g/dL或血细胞比容>49%的为6.48%；而血红蛋白>160g/L的女性比例为0.22%，血细胞比容>48%的为0.11%，血红蛋白>160g/L或血细胞比容>48%的为0.28%。
单纯使用提议的血红蛋白/血细胞比容水平作为红细胞增多症的定义可能会导致不必要诊断检查的大幅增加。在血红蛋白水平处于临界值的情况下，仅当存在与骨髓增殖性肿瘤（MPN）相关的临床和/或实验室特征时，才应进行PV的诊断检查。
