Lee Sue J, Stepniewska Kasia, Anstey Nicholas, Ashley Elizabeth, Barnes Karen, Binh Tran Quang, D'Alessandro Umberto, Day Nicholas P J, de Vries Peter J, Dorsey Grant, Guthmann Jean-Paul, Mayxay Mayfong, Newton Paul, Nosten Francois, Olliaro Piero, Osario Lyda, Pinoges Loretxu, Price Ric, Rowland Mark, Smithuis Frank, Taylor Robert, White Nicholas J
Mahidol-Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Faculty of Tropical Medicine, 3rd Floor, 60th Anniversary Chalermprakiat Building, 420/6 Ratchawithi Rd, Ratchathewi District, Bangkok 10400, Thailand.
Malar J. 2008 Aug 2;7:149. doi: 10.1186/1475-2875-7-149.
Malaria is a very important cause of anaemia in tropical countries. Anaemia is assessed either by measurement of the haematocrit or the haemoglobin concentration. For comparisons across studies, it is often necessary to derive one measure from the other.
Data on patients with slide-confirmed uncomplicated falciparum malaria were pooled from 85 antimalarial drug trials conducted in 25 different countries, to assess the haemoglobin/haematocrit relationship at different time points in malaria. Using a linear random effects model, a conversion equation for haematocrit was derived based on 3,254 measurements from various time points (ranging from day 0 to day 63) from 1,810 patients with simultaneous measurements of both parameters. Haemoglobin was also estimated from haematocrit with the commonly used threefold conversion.
A good fit was obtained using Haematocrit = 5.62 + 2.60 * Haemoglobin. On average, haematocrit/3 levels were slightly higher than haemoglobin measurements with a mean difference (+/- SD) of -0.69 (+/- 1.3) for children under the age of 5 (n = 1,440 measurements from 449 patients).
Based on this large data set, an accurate and robust conversion factor both in acute malaria and in convalescence was obtained. The commonly used threefold conversion is also valid.
在热带国家，疟疾是导致贫血的一个非常重要的原因。贫血可通过测量血细胞比容或血红蛋白浓度来评估。为了在不同研究之间进行比较，常常需要从一种测量方法推导出另一种测量方法。
汇总在25个不同国家进行的85项抗疟药物试验中经血涂片确诊的非复杂性恶性疟患者的数据，以评估疟疾不同时间点的血红蛋白/血细胞比容关系。使用线性随机效应模型，基于1810名同时测量了这两个参数的患者在不同时间点（从第0天到第63天）的3254次测量结果，推导出了血细胞比容的转换方程。还使用常用的三倍转换法从血细胞比容估算血红蛋白。
使用血细胞比容 = 5.62 + 2.60×血红蛋白可获得良好的拟合。平均而言，5岁以下儿童的血细胞比容/3水平略高于血红蛋白测量值，449名患者的1440次测量的平均差值（±标准差）为 -0.69（±1.3）。
基于这个大数据集，在急性疟疾和恢复期都获得了准确且可靠的转换因子。常用的三倍转换也是有效的。
