Oloo A J, Ondijo S O, Genga I O, Boriga D A, Owaga M L, Ngare D, Gathecha E
Vector Biology and Control Research Centre, Kenya Medical Research Institute (KEMRI), Kisumu, Kenya.
East Afr Med J. 1994 May;71(5):297-9.
The conventional peripheral blood film method used to diagnose malaria is characterized by low sensitivity in scanty parasitaemia and can be time consuming when required to rule out infection. The Quantitative Buffy Coat (QBC) method has been proposed to be quicker and more sensitive. We conducted a malaria survey in April 1992 among school-children in Kisumu (holoendemic) and Webuye (hypoendemic) areas of Western Kenya. Peripheral blood samples were examined by thick blood smear (TBS) stained with Giemsa solution, and by the QBC method. A total of 360 paired samples were analyzed. There were 175 (49%) positive TBS and 201 (56%) positive QBC. Of the 185 TBS classified as negative, 30 (16%) were positive by QBC. When parasite density by TBS was > or = 100/300 WBCs, the sensitivity of QBC was 100%. Overall sensitivity for QBC was 98%, with a specificity of 84%. Negative predictive value for the QBC was 98%, and had a calculated accuracy of 92%. It took an average of 44 minutes to process a TBS and a further average of 2.6 minutes to examine a negative TBS. For the QBC the mean time to process and to examine was 7.09 and 1.04 minutes respectively. We conclude that the QBC is quicker, with high sensitivity, and will prove useful in clinical and epidemiological screening, especially when parasitaemia is low.
用于诊断疟疾的传统外周血涂片法的特点是在疟原虫血症较少时敏感性较低，并且在需要排除感染时可能耗时较长。定量血沉棕黄层（QBC）法被认为更快且更敏感。1992年4月，我们在肯尼亚西部的基苏木（高度流行区）和韦布耶（低度流行区）对学童进行了疟疾调查。外周血样本通过用吉姆萨溶液染色的厚血涂片（TBS）以及QBC法进行检测。总共分析了360对样本。TBS检测阳性的有175例（49%），QBC检测阳性的有201例（56%）。在185例被分类为TBS阴性的样本中，有30例（16%）通过QBC检测为阳性。当TBS检测的寄生虫密度≥100/300个白细胞时，QBC的敏感性为100%。QBC的总体敏感性为98%，特异性为84%。QBC的阴性预测值为98%，计算得出的准确性为92%。处理一份TBS平均需要44分钟，检查一份阴性TBS平均还需要2.6分钟。对于QBC，处理和检查的平均时间分别为7.09分钟和1.04分钟。我们得出结论，QBC更快，具有高敏感性，并且在临床和流行病学筛查中将会证明是有用的，特别是在疟原虫血症较低时。
