National Institute for Medical Research, Amani Centre, Muheza, Tanzania.
Trop Med Int Health. 2011 May;16(5):545-50. doi: 10.1111/j.1365-3156.2011.02737.x. Epub 2011 Feb 14.
To compare the performance of the Paracheck™ rapid diagnostic test (RDT) with microscopy for diagnosing malaria in hospitalised children.
Children aged between 2 months and 13 years with fever were enrolled in the study over 1 year. A standard clinical history and examination were recorded and blood drawn for culture, complete blood count, Paracheck™ RDT and double-read blood slide.
Of 3639 children enrolled, 2195 (60.3%) were slide positive. The sensitivity and specificity of Paracheck were 97.5% (95% CI 96.9-98.0) and 65.3% (95% CI 63.8-66.9), respectively. There was an inverse relationship between age-specific prevalence of parasitaemia and Paracheck specificity. In logistic regression model, false-positive Paracheck results were significantly associated with pre-admission use of antimalarial drug (OR 1.44, 95% CI 1.16-1.78), absence of current fever (OR 0.64, 95% CI 0.52-0.79) and non-typhi Salmonella bacteraemia (OR 3.89. 95% CI 2.27-6.63). In spite of high sensitivity, 56/2195 (2.6%) of true infections were Paracheck negative and 8/56 (14.3%) were in patients with >50,000 parasites/μl.
Paracheck had poor specificity in diagnosing malaria in severely ill children; this was likely to be due to HRP2 persistence following recent parasite clearance. The combination of positive Paracheck and negative blood slide results identified a group of children at high risk of non-typhi Salmonella infection. While Paracheck was highly sensitive, some high-density infections were missed. For children with severe febrile illness, at least two reliable negative parasitological test results should be available to justify withholding antimalarial treatment; the optimal choice of these has yet to be identified.
比较 Paracheck™ 快速诊断检测（RDT）与显微镜检查在住院儿童疟疾诊断中的性能。
在一年的时间里，招募了年龄在 2 个月至 13 岁之间、有发热症状的儿童参加这项研究。记录了标准的临床病史和检查，并抽取血液进行培养、全血细胞计数、Paracheck™ RDT 和双读血片。
在 3639 名入组儿童中，2195 名（60.3%）血片阳性。Paracheck 的敏感性和特异性分别为 97.5%（95%CI 96.9-98.0）和 65.3%（95%CI 63.8-66.9）。寄生虫血症的年龄特异性患病率与 Paracheck 的特异性呈反比关系。在逻辑回归模型中，假阳性 Paracheck 结果与入院前使用抗疟药物（OR 1.44，95%CI 1.16-1.78）、无当前发热（OR 0.64，95%CI 0.52-0.79）和非伤寒沙门氏菌菌血症（OR 3.89，95%CI 2.27-6.63）显著相关。尽管敏感性高，但 2195 例真感染中有 56 例（2.6%）Paracheck 检测结果为阴性，其中 8 例（14.3%）患者的寄生虫数>50,000/μl。
Paracheck 在诊断重症儿童疟疾时特异性较差；这可能是由于近期寄生虫清除后 HRP2 的持续存在。阳性 Paracheck 和阴性血片结果的组合确定了一组有非伤寒沙门氏菌感染高风险的儿童。虽然 Paracheck 的敏感性很高，但还是漏掉了一些高密度感染。对于患有严重发热疾病的儿童，至少需要两个可靠的阴性寄生虫学检测结果来证明不使用抗疟药物治疗是合理的；目前还需要确定这些检测方法的最佳选择。
