Avila Priscilla Elisangela, Kirchgatter Karin, Brunialti Karen Cristina S, Oliveira Alessandra M, Siciliano Rinaldo F, Di Santi Silvia Maria
Núcleo de Estudos em Malária, Superintendência de Controle de Endemias, São Paulo, Brasil.
Rev Inst Med Trop Sao Paulo. 2002 Sep-Oct;44(5):293-6. doi: 10.1590/s0036-46652002000500012.
The present study was carried out to evaluate the Malar-Check trade mark Pf test, an immunochromatographic assay that detects Plasmodium falciparum Histidine Rich Protein II, does not require equipment, and is easy and rapid to perform. In dilution assays performed to test sensitivity against known parasite density, Malar-Check were compared with thick blood smear (TBS), the gold standard for diagnosis. Palo Alto isolate or P. falciparum blood from patients with different parasitemias was used. The average cut-off points for each technique in three independent experiments were 12 and 71 parasites/mm3 (TBS and Malar-Check, respectively). In the field assays, samples were collected from patients with fever who visited endemic regions. Compared to TBS, Malar-Check yielded true-positive results in 38 patients, false-positive results in 3, true-negative results in 23, and false-negative result in 1. Malar-Check performed with samples from falciparum-infected patients after treatment showed persistence of antigen up to 30 days. Malar-Check should aid the diagnosis of P. falciparum in remote areas and improve routine diagnosis even when microscopy is available. Previous P. falciparum infection, which can determine a false-positive test in cured individuals, should be considered. The prompt results obtained with the Malar-Check for early diagnosis could avoid disease evolution to severe cases.
本研究旨在评估Malar-Check商标的疟原虫检测试验，这是一种免疫层析检测法，可检测恶性疟原虫富含组氨酸蛋白II，无需设备，操作简便快捷。在针对已知寄生虫密度进行敏感性测试的稀释试验中，将Malar-Check与厚血涂片（TBS）（诊断的金标准）进行了比较。使用了来自帕洛阿尔托分离株或不同寄生虫血症患者的恶性疟原虫血液。在三个独立实验中，每种技术的平均截断点分别为12和71个寄生虫/立方毫米（分别为TBS和Malar-Check）。在现场试验中，从前往流行地区就诊的发热患者中采集样本。与TBS相比，Malar-Check在38例患者中得出真阳性结果，3例假阳性结果，23例真阴性结果，1例假阴性结果。对恶性疟原虫感染患者治疗后的样本进行Malar-Check检测显示，抗原可持续存在30天。Malar-Check应有助于偏远地区恶性疟原虫的诊断，即使在有显微镜检查的情况下也能改善常规诊断。应考虑既往恶性疟原虫感染，这可能会在治愈个体中导致假阳性检测结果。Malar-Check获得的快速结果用于早期诊断可避免疾病发展为重症病例。
