Comparative evaluation of 11 commercialized rapid diagnostic tests for detecting Trypanosoma cruzi antibodies in serum banks in areas of endemicity and nonendemicity

Chagas disease is one of the main public health issues in Latin America. Increasingly during the past few decades, Trypanosoma cruzi infection has been detected in North America, Europe, and the Western Pacific, mainly as a result of population movement. The limited availability of rapid serological diagnostic tests hinders rapid diagnosis and early treatment in areas of endemicity and nonendemicity. In collaboration with 11 national reference laboratories (NRLs) from different geographical areas, we evaluated the performances of commercialized serological rapid diagnostic tests (RDT) for T. cruzi infection. Eleven commercialized T. cruzi infection RDTs were evaluated on a total of 474 samples extensively tested with at least three different techniques for Chagas disease, maintained at controlled low temperatures, and stored in the serum banks of the 11 NRLs. We measured the sensitivity, specificity, and concordance of each RDT and provided an additional questionnaire to evaluate its ease of use. The selected RDTs in this study were performed under controlled laboratory conditions. Out of the 11 RDTs, we found 8 of them to be useful, with the cassette format favored over the strip. We did not observe significant differences in RDT performances in the different regions. Overall, the performance results were lower than those disclosed by the manufacturers. The results of this evaluation validate the possibility of using RDTs to diagnose Chagas disease, thereby decreasing the time to treatment at a primary health care facility for patients who are willing to be treated. Further studies should be conducted in the laboratory and in the field to confirm these data, expressly to evaluate reproducibility in resource-limited settings, or using whole blood in clinical settings in areas of endemicity and nonendemicity

Detection of hepatitis B virus DNA by the polymerase chain reaction in anti-HBE positive chronic hepatitis B patients

Detection of HBV-DNA by PCR was compared with other serological markers (HBsAg, HBeAg and anti-HBe) in a series of49 Chronic Hepatitis B patients, including 12 with a spontaneous clearance of HBsAg. None of these HBsAg negative cases were PCR positive, but 33/37 (89.2%) HBsAg positive cases were PCR positive (p A detecção do DNA do Vírus da Hepatite B pela Reação em Cadeia da Polimerase (PCR) foi comparada com os outros marcadores sorológicos virais (AgHBs, AgHBe e anti-HBe) numa série de 49 pacientes com hepatite crônica B, incluindo 12 que apresentaram clareamento espontâneo do AgHBs. Nenhum caso AgHBs negativo foi PCR positivo, mas 33/37 (89,2%) dos casos AgHBs positivos foram PCR positivos (p < 0,0001). Entre as amostras AgHBs positivas, 9 foram AgHBc positivas e anti-HBe negativas, todas elas PCR positivas. Outros 3 pacientes foram AgHBe e anti-HBe positivos, todos também PCR positivos. Um terceiro grupo incluía 21 pacientes anti-HBe positivos e anti-HBe negativos: 19 foram PCR positivos e 2 PCR negativos. Os últimos 4 casos foram AgHBe e anti-HBe negativos, sendo 2 destes PCR positivos. A detecção de casos virêmicos anti-HBe positivos sugere que as variantes preC do VHB podem também estar presentes em nosso país. Em conclusão, a "fase de integração viral" da hepatite crônica B parece ser muito menos frequente do que se imaginava previamente, quando apenas se dispunha das técnicas de detecção de AgHBe e DNA por hibridização. O novo termo "fase de baixa replicação baixa" parece ser melhor que o anterior "fase de integração viral"

Detecção do DNA do vírus da Hepatite B pela reação em cadeia da polimerase em pacientes com Hepatite Crônica B soropositivos para o anticorpo Anti-HBe

Detection of HBV-DNA by PCR was compared with other serological markers (HBsAg, HBeAg and anti-HBe) in a series of49 Chronic Hepatitis B patients, including 12 with a spontaneous clearance of HBsAg. None of these HBsAg negative cases were PCR positive, but 33/37 (89.2%) HBsAg positive cases were PCR positive (p < 0.0001). Among HBsAg positive samples, nine cases were HBeAg positive and anti-HBe negative, all of them PCR positive. Other 3 patients were HBeAg and anti-HBe positive and these cases were also found PCR positive. A third group included 21 patients anti-HBe positive and HBeAg negative: 19 of them were PCR positive and 2 were PCR negative. The last 4 cases were HBeAg and anti-HBe negative, two of them were PCR positive. The detection of anti-HBe viremic cases in the present series suggest that preC variants could occur in our country. In conclusion, the integrated phase o f chronic hepatitis B seems to be less frequent than it was assumed, when only HBeAg or dot blot hybridization techniques were used. The new term "low replication phase" might favorably replace the former "integrated phase".A detecção do DNA do Vírus da Hepatite B pela Reação em Cadeia da Polimerase (PCR) foi comparada com os outros marcadores sorológicos virais (AgHBs, AgHBe e anti-HBe) numa série de 49 pacientes com hepatite crônica B, incluindo 12 que apresentaram clareamento espontâneo do AgHBs. Nenhum caso AgHBs negativo foi PCR positivo, mas 33/37 (89,2%) dos casos AgHBs positivos foram PCR positivos (p < 0,0001). Entre as amostras AgHBs positivas, 9 foram AgHBc positivas e anti-HBe negativas, todas elas PCR positivas. Outros 3 pacientes foram AgHBe e anti-HBe positivos, todos também PCR positivos. Um terceiro grupo incluía 21 pacientes anti-HBe positivos e anti-HBe negativos: 19 foram PCR positivos e 2 PCR negativos. Os últimos 4 casos foram AgHBe e anti-HBe negativos, sendo 2 destes PCR positivos. A detecção de casos virêmicos anti-HBe positivos sugere que as variantes preC do VHB podem também estar presentes em nosso país. Em conclusão, a "fase de integração viral" da hepatite crônica B parece ser muito menos frequente do que se imaginava previamente, quando apenas se dispunha das técnicas de detecção de AgHBe e DNA por hibridização. O novo termo "fase de baixa replicação baixa" parece ser melhor que o anterior "fase de integração viral"