Department of Neurology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
Department of Clinical Sciences, Rheumatology, Lund University, Skåne University Hospital, Lund, Sweden.
Eur J Haematol. 2020 Jan;104(1):46-54. doi: 10.1111/ejh.13334. Epub 2019 Nov 22.
Iron deficiency in polycythaemia vera (PV) may impact the validity of the haematocrit (HCT), since HCT is red blood cell count (RBC) × mean corpuscular volume (MCV).
To investigate (a) the effect of microcytosis on HCT, (b) the erythrocyte sedimentation rate (ESR) as a possible additional diagnostic marker for PV.
This study included 182 subjects: 39 with PV, 27 with essential thrombocythemia (ET) and 116 suspected of myeloproliferative neoplasm (MPN) with a secondary cause for either thrombocytosis or erythrocytosis.
Patients with PV had significantly lower ratio of MCV and serum ferritin compared to MPN suspects. A good correlation of RBC versus HCT was found for PV and MPN subjects when individuals with microcytosis were excluded (R = .87 in PV and R = .82 in MPN suspects). We found a specificity of 98% and a sensitivity of 37% for ESR <2 mm in the diagnosis of PV.
The RBC may more precisely reflect the total red cell mass and accordingly the hypercoagulable state of the PV patient, which is integrated in the ESR. A combination of RBC and ESR is proposed as a novel tool to substitute the Hb concentration and the HCT in the diagnosis of PV.
真性红细胞增多症（PV）中的铁缺乏可能会影响红细胞压积（HCT）的准确性，因为 HCT 是红细胞计数（RBC）×平均红细胞体积（MCV）。
研究（a）小红细胞症对 HCT 的影响，（b）红细胞沉降率（ESR）作为 PV 的另一种可能的诊断标志物。
本研究纳入了 182 名受试者：39 名 PV 患者、27 名原发性血小板增多症（ET）患者和 116 名疑似骨髓增殖性肿瘤（MPN）患者，这些患者的血小板增多或红细胞增多有继发原因。
与 MPN 疑似患者相比，PV 患者的 MCV 和血清铁蛋白比值明显更低。当排除小红细胞症患者后，PV 和 MPN 患者的 RBC 与 HCT 之间存在良好的相关性（PV 中 R = .87，MPN 疑似患者中 R = .82）。我们发现 ESR <2 毫米在诊断 PV 中的特异性为 98%，敏感性为 37%。
RBC 可能更准确地反映总红细胞质量，从而反映 PV 患者的高凝状态，这与 ESR 相关。建议将 RBC 和 ESR 联合作为替代 Hb 浓度和 HCT 的新工具用于诊断 PV。
