Ferreira A W, Belem Z R, Moura M E, Camargo M E
Instituto de Medicina Tropical, São Paulo, Brasil.
Rev Inst Med Trop Sao Paulo. 1991 Mar-Apr;33(2):123-8.
In the serological diagnosis of Chagas disease large divergences may be found even between laboratories with experience, as a consequence of different criteria for the standardization of the tests. To standardize a immunoenzymatic test developed primarily for screening blood donors, serum panels were carefully chosen so as to best represent chagasic and non-chagasic populations. Produced for the highest sensibility and stability, the new reagent (bioELISA cruzi, Biolab Diagnóstica S/A, Brasil), was tested in serum from 1648 patients 219 with Chagas disease and 104 with other diseases, plus a comparison with well standardized immunofluorescence and hemagglutination tests in 1325 sera. In the immunoenzymatic assays, the cut off was indicated by the absorbance value of a chagasic serum showing a minimal reactivity. ELISA sensibility was 0.9954 and specificity 0.9969, as co-negativity. False positive results were absent with sera from syphilis, toxoplasmosis, mononucleosis and high titered sera for antistreptolysin 0 antibodies. However they were seen in 5 to 15 cases of tegumentar leishmaniasis, 1 of 12 Kala-azar 1 of 15 rheumatoid arthritis and 1 of 12 systemic lupus erythematosus. The high sensibility in chagasics and high specificity in the general population indicate the confiability of the immunoenzymatic assay for screening blood donors and even to confirm a clinical diagnosis of Chagas' disease.
在恰加斯病的血清学诊断中，即使是经验丰富的实验室之间也可能存在很大差异，这是由于检测标准化的标准不同所致。为了对主要用于筛查献血者的免疫酶检测进行标准化，精心挑选了血清样本组，以最好地代表恰加斯病患者和非恰加斯病患者群体。新试剂（生物ELISA克氏锥虫检测试剂盒，Biolab Diagnóstica S/A，巴西）为实现最高的灵敏度和稳定性而生产，在1648例患者的血清中进行了检测，其中219例患有恰加斯病，104例患有其他疾病，另外还在1325份血清中与标准化良好的免疫荧光和血凝试验进行了比较。在免疫酶检测中，临界值由显示最小反应性的恰加斯病血清的吸光度值确定。ELISA的灵敏度为0.9954，特异性为0.9969，为共同阴性。梅毒、弓形虫病、单核细胞增多症患者的血清以及抗链球菌溶血素0抗体高滴度血清均未出现假阳性结果。然而，在5至15例皮肤利什曼病、12例黑热病中的1例、15例类风湿性关节炎中的1例以及12例系统性红斑狼疮中的1例中出现了假阳性结果。恰加斯病患者中的高灵敏度和普通人群中的高特异性表明免疫酶检测对于筛查献血者甚至确诊恰加斯病临床诊断的可靠性。
