Abstract：
The landmark value of mean corpuscular volume (MCV) in the diagnosis and classification of anemias has been established more than a century ago. In contrast, the importance of MCV assessment in patients with elevated hemoglobin and hematocrit is not nearly as appreciated.
This case describes a patient who exhibited long-standing macrocytosis (elevated MCV) that contributed to elevated hemoglobin and hematocrit levels thus mimicking a diagnosis of polycythemia vera.
The case demonstrates that discounting the MCV effect on hemoglobin/hematocrit levels can lead to potential errors in interpretation of blood tests and misdiagnosis.
This case describes a patient who exhibited long-standing macrocytosis (elevated MCV) that contributed to elevated hemoglobin and hematocrit levels thus mimicking a diagnosis of polycythemia vera.
The case demonstrates that discounting the MCV effect on hemoglobin/hematocrit levels can lead to potential errors in interpretation of blood tests and misdiagnosis.
摘要：
一个多世纪前就已经确定了平均红细胞体积（MCV）在贫血的诊断和分类中的标志值。相比之下,在血红蛋白和血细胞比容升高的患者中,MCV评估的重要性几乎没有得到重视.
该病例描述了一名患者，该患者表现出长期的大红细胞增多症（MCV升高），导致血红蛋白和血细胞比容水平升高，从而模仿真性红细胞增多症的诊断。
该病例表明，降低MCV对血红蛋白/血细胞比容水平的影响可能会导致解释血液检查和误诊的潜在错误。
该病例描述了一名患者，该患者表现出长期的大红细胞增多症（MCV升高），导致血红蛋白和血细胞比容水平升高，从而模仿真性红细胞增多症的诊断。
该病例表明，降低MCV对血红蛋白/血细胞比容水平的影响可能会导致解释血液检查和误诊的潜在错误。
