Tanpradist S, Tharavanij S, Yamokgul P, Bualombai P, Wongchotigul V, Singhasivanon P, Patarapotikul J, Thammapalerd N, Prasittisuk C, Tantanasrikul S
Department of Communicable Diseases, Ministry of Public Health, Devavesm Palace, Bangkok, Thailand.
Southeast Asian J Trop Med Public Health. 1995 Mar;26(1):38-45.
Monoclonal antibody-based ELISA and QBC (quantitative buffy coat analysis) were tested in two endemic areas with low and high incidence of malaria in Kanchanaburi Province, West Thailand with annual parasite incidence in 1992 of 119 and 5 per 1,000 population, respectively. The numbers of individuals positive by thick blood film examination (TBF) for P. falciparum with or without P. vivax, and P. vivax only were 82 and 69, respectively. The detection limit of ELISA was 10 parasites/10(6) red blood cells (RBC) (0.001% parasitemia). Of 1,095 individuals involved in the study at the beginning of the study, ELISA showed sensitivity, specificity, positive predictive value and negative predictive value of 78.1%, 94.9%, 72% and 98.1%, respectively. Nine of 18 (50%) TBF-positive but ELISA-positive individuals had parasitemia of less than 10 parasites/10(6) RBC. High and low incidence areas did not affect the validity of our result. Regression analysis showed good correlation between log parasitemia and ELISA percent OD increase (Y = 0 + 64.9*logX, r = 0.65), and agreement between TBF and ELISA results was 95.9%. In a fortnightly follow-up, in 82 TBF-positive individuals, both ELISA and TBF positive rates correlatively declined with agreement of 96.3%. With samples taken on the first day of the study, the TBF and QBC results were also correlated with agreement of 95.8% for P. falciparum, 95.6% for P. vivax. During 8 week follow-up involving altogether 191 samples, agreement between TBF and QBC results were 87.4% for P. falciparum. QBC detected more cases with P. falciparum infections but detected smaller number of cases with P. vivax infections.
基于单克隆抗体的酶联免疫吸附测定（ELISA）和定量血沉棕黄层分析（QBC）在泰国西部北碧府疟疾发病率低和高的两个流行地区进行了测试，1992年的年寄生虫发病率分别为每千人口119例和5例。通过厚血膜检查（TBF）检测到的恶性疟原虫阳性个体数量（无论有无间日疟原虫）以及仅间日疟原虫阳性个体数量分别为82例和69例。ELISA的检测限为10个寄生虫/10⁶个红细胞（RBC）（0.001%的寄生虫血症）。在研究开始时参与研究的1095名个体中，ELISA的敏感性、特异性、阳性预测值和阴性预测值分别为78.1%、94.9%、72%和98.1%。18名TBF阳性但ELISA阳性的个体中有9名（50%）寄生虫血症低于10个寄生虫/10⁶个RBC。高发病率和低发病率地区不影响我们结果的有效性。回归分析表明，对数寄生虫血症与ELISA光密度增加百分比之间存在良好的相关性（Y = 0 + 64.9*logX，r = 0.65），TBF与ELISA结果之间的一致性为95.9%。在为期两周的随访中，82名TBF阳性个体中，ELISA和TBF阳性率均相应下降，一致性为96.3%。在研究第一天采集的样本中，TBF和QBC结果也具有相关性，恶性疟原虫的一致性为95.8%，间日疟原虫的一致性为95.6%。在总共191个样本的8周随访期间，TBF与QBC结果之间对于恶性疟原虫的一致性为87.4%。QBC检测到更多恶性疟原虫感染病例，但检测到的间日疟原虫感染病例较少。
