Iqbal Jamshaid, Khalid Nabila, Hira Parsotam Ravjee
Department of Microbiology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait.
Adv Exp Med Biol. 2003;531:135-48. doi: 10.1007/978-1-4615-0059-9_10.
Recently introduced rapid nonmicroscopic immunocapture assays for the diagnosis of malaria infection are being evaluated for their sensitivity and specificity in various epidemiological settings. A Plasmodium falciparum histidine-rich protein-2 (PfHRP-2)-based assay (ICT malaria Pf assay) was evaluated for its performance and compared to that of Giemsa-stained thick blood film microscopy. Of the 515 patients tested, 163 were positive for malaria parasites on thick blood film microscopy: 87 were infected with P. vivax; 63 with P. falciparum; 1 with P. malariae; and 12 with both P. falciparum and P. vivax. The ICT assay detected 53 P. falciparum infections and, as expected, failed to detect all but one case of P. vivax. Three cases of mixed infections were also not detected by this assay. The performance of the ICT assay in diagnosing P. falciparum infection was comparable to that of microscopy. The sensitivity of the ICT assay was 82% and the specificity 99.0%. The ICT assay also detected 4 false-positive cases. These patients reported treatment with chloroquine in the previous 2-5 weeks. The specificity of the assay was evaluated in different groups of patients, who had tested negative for malaria infection by microscopy. These patients were selected from different disease groups: rheumatoid arthritis; hepatitis C; toxoplasmosis; schistosomiasis; and hydatid disease. Of the 225 patients studied, 133 were positive for rheumatoid factor. Thirty-five (26%) of the 133 patients had false positive-reactions with the ICT assay, while only four had false positive-reactions with the OptiMAL test. After the rheumatoid factor was absorbed 33 of the 35 false-positive specimens were negative when retested with the ICT assay. Our study shows that the PfHRP-2-based ICT assay gave a false positive-reaction in 26% of the patients who had rheumatoid factors, but were negative for malaria by microscopy. We conclude that new rapid nonmicroscopic methods for the diagnosis of malaria that complement or support blood film microscopy would be of great use in the diagnosis and treatment of patients with malaria and also in epidemiological studies.
最近推出的用于疟疾感染诊断的快速非显微镜免疫捕获检测方法正在不同的流行病学环境中评估其敏感性和特异性。对一种基于恶性疟原虫富含组氨酸蛋白2（PfHRP-2）的检测方法（ICT疟疾Pf检测法）的性能进行了评估，并与吉姆萨染色厚血膜显微镜检查法进行了比较。在接受检测的515名患者中，163名患者的厚血膜显微镜检查显示疟原虫阳性：87名感染间日疟原虫；63名感染恶性疟原虫；1名感染三日疟原虫；12名同时感染恶性疟原虫和间日疟原虫。ICT检测法检测出53例恶性疟原虫感染，正如预期的那样，除1例间日疟原虫感染外，未能检测出其他所有间日疟原虫感染病例。该检测法也未检测出3例混合感染病例。ICT检测法在诊断恶性疟原虫感染方面的性能与显微镜检查法相当。ICT检测法的敏感性为82%，特异性为99.0%。ICT检测法还检测出4例假阳性病例。这些患者报告在之前2至5周内接受过氯喹治疗。在通过显微镜检查疟疾感染呈阴性的不同患者组中评估了该检测法的特异性。这些患者选自不同疾病组：类风湿性关节炎；丙型肝炎；弓形虫病；血吸虫病；以及包虫病。在研究的225名患者中，133名类风湿因子呈阳性。133名患者中有35名（26%）在ICT检测法中出现假阳性反应，而在OptiMAL检测法中只有4名出现假阳性反应。在用类风湿因子吸附后，35例假阳性标本中有33例在再次用ICT检测法检测时呈阴性。我们的研究表明，基于PfHRP-2的ICT检测法在类风湿因子呈阳性但显微镜检查疟疾呈阴性的患者中有26%出现假阳性反应。我们得出结论，用于疟疾诊断的新的快速非显微镜方法，若能补充或支持血膜显微镜检查，将在疟疾患者的诊断和治疗以及流行病学研究中非常有用。
