RESUMO CONTEXTO: O sangramento colorretal é considerado um sinal de alarme e não deve ser ignorado. O resultado positivo de um teste de pesquisa de sangue oculto nas fezes (PSOF) requer investigação complementar com colonoscopia, exame invasivo e de alto custo. Justifica-se, portanto, a aplicação de um teste diagnóstico mais sensível e específico. No presente estudo, foram avaliados quatro diferentes testes de PSOF em 176 pacientes submetidos à colonoscopia e seus resultados foram comparados. OBJETIVO: Avaliar a sensibilidade, a especificidade e os valores de predição dos testes químico e imunoquímico de PSOF em pacientes submetidos à colonoscopia e avaliar o grau de concordância entre os testes de PSOF e a colonoscopia. MÉTODOS: Pacientes com indicação de realizar colonoscopia foram submetidos também à PSOF pelo método químico (o-toluidina) e pelo método imunoquímico, empregando três kits comerciais disponíveis no mercado. Fundamentado nos achados endoscópicos, a colonoscopia foi categorizada em positiva ou negativa, de acordo com a possível fonte de sangramento colorretal. O grau de concordância entre os testes de PSOF foi avaliado pelo índice kappa. RESULTADOS: Quarenta e quatro (25%) colonoscopias foram categorizadas como positivas quanto à fonte de sangramento colorretal. O teste da o-toluidina mostrou menor concordância que os testes imunoquímicos, os quais apresentaram moderada concordância com a colonoscopia. O teste da o-toluidina revelou menor sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo. CONCLUSÃO: Os testes imunoquímicos revelaram maior sensibilidade, especificidade e valores de predição na detecção de sangramento colorretal. Os testes imunoquímicos apresentaram melhores índices de concordância com a colonoscopia, quando comparados ao teste da o-toluidina.

ABSTRACT BACKGROUND: Colorectal bleeding is a warning sign that may be identified by fecal occult blood testing. A positive fecal occult blood test result requires a subsequent colonoscopy, a costly and invasive examination. Therefore, the use of diagnostic tests with optimal sensitivity and specificity is warranted. In this study, we evaluated four different fecal occult blood tests in 176 patients undergoing colonoscopy and compared their results. OBJECTIVE: To assess the sensitivity, specificity and predictive values of chemical and immunochemical fecal occult blood tests in patients undergoing colonoscopy and to evaluate the degree of concordance between the tests and colonoscopy. METHODS: Patients with indications for colonoscopy also underwent fecal occult blood testing by chemical (toluidine test) and immunochemical methods, employing three commercially available kits. Based on the endoscopic findings, the colonoscopy was rated as positive or negative for colorectal bleeding. The degree of concordance between the fecal occult blood tests and the colonoscopy was evaluated by the kappa index. RESULTS: Forty-four (25%) colonoscopies were categorized as positive for colorectal bleeding. The toluidine test presented lower concordance than the immunochemical tests, which showed moderate concordance with the colonoscopy. The toluidine test had the least sensitivity, specificity, and positive and negative predictive values. CONCLUSION: The immunochemical fecal occult blood tests showed greater sensitivity, specificity and predictive values in detecting colorectal bleeding. The immunochemical tests had superior indexes of agreement with colonoscopy compared to the toluidine test.

O objetivo deste estudo foi comparar métodos por kit colorimétrico e por ensaio imunossorvente ligado à enzima (ELISA) para quantificar o ácido 5-hidroxi-indolacético urinário com a técnica de Goldenberg, explorando o potencial de substituí-la. Amostras de urina de 24 horas foram testadas pela técnica de Goldenberg e com os kits. A concordância foi quase perfeita, tanto para a comparação do ensaio de Goldenberg com o kit colorimétrico quanto para com o kit ELISA, considerando normal o valor de corte de ≤ 7.5 mg/24h. Portanto, ambos os kits seriam boa alternativa para a técnica de Goldenberg devido à praticidade e à concordância entre os valores.

The aim of this study was to compare the colorimetric "kit" and enzyme-linked immunosorbent assay (ELISA) methods to quantify urinary 5-hydroxyindoleacetic acid through the Goldenberg's technique, exploring the potential of replacing it. 24-hour urine samples were tested by Goldenberg's assay and compared with kits. The agreement was almost perfect for the comparison of Goldenberg's assay with both colorimetric kit, and with ELISA kit, considering ≤ 7.5 mg/24h normal cutoff value. Therefore, both "kits" would be good alternatives to Goldenberg's technique due to practicality and agreement between values.

O objetivo desse trabalho foi avaliar o teste rápido de antígeno de H. pylori nas fezes (One step H. pylori antigen test, ACON laboratories, San Diego, USA; Prime diagnostics, São Paulo), usando teste respiratório com uréia marcada com 13C (TRU-13C), como padrão ouro. Noventa e oito pacientes assintomáticos ou com dispepsia participaram do estudo. Sessenta e nove eram mulheres; a média de idade dos pacientes foi de 45.76 ± 14.59 (14 a 79 anos). No grupo H. pylori positivo, o teste rápido detectou antígenos de H. pylori nas fezes em 44 dos 50 pacientes positivos (sensibilidade de 88%; 95% IC: 75.7-95.5%), com seis falso-negativos; e no grupo H. pylori negativo, 42 apresentaram resultados negativos (especificidade de 87,5%; 95% IC: 74.7-95.3%), com seis falso-positivos, mostrando concordância substancial (índice Kappa = 0.75; p < 0.0001; 95% IC: 0.6-0.9). Quarenta e quatro dos 50 que tiveram teste de antígeno fecal positivo eram H. pylori positivos, sendo o VPP do teste 88% (95% IC: 75.7-95.5%), e 42 pacientes com teste de antígeno fecal negativo eram H. pylori negativos, com VPN de 87,5% (95% IC: 74.7-95.3%). Concluímos que o teste de antígeno fecal imunocromatográfico pode ser usado como alternativa ao teste respiratório para diagnóstico de infecção pelo H. pylori, principalmente em países em desenvolvimento.

The aim of this study was to validate the rapid lateral flow Helicobacter pylori stool antigen test (One step H. pylori antigen test, ACON laboratories, San Diego, USA; Prime diagnostics, São Paulo), using 13C-Urea Breath Test as the gold standard for H. pylori infection diagnosis. A total of 98 consecutive patients, asymptomatic or dyspeptic, entered the study. Sixty-nine were women, with a mean age of 45.76 ± 14.59 years (14 to 79 years). In the H. pylori-positive group, the rapid stool antigen test detected H. pylori antigen in 44 of the 50 positive patients (sensitivity 88%; 95% CI: 75.7-95.5%), and six false-negative; and in the H. pylori-negative group 42 presented negative results (specificity 87.5%; 95% CI: 74.7-95.3%), and six false-positive, showing a substantial agreement (Kappa Index = 0.75; p < 0.0001; 95% CI: 0.6-0.9). Forty four of fifty patients that had positive stool antigen were H. pylori-positive, the PPV of the stool antigen test was 88% (95% CI: 75.7-95.5%), and 42 patients with negative stool antigen test were H. pylori-negative, the NPV of the stool antigen test was 87.5% (95% CI: 74.7-95.3%). We conclude that the lateral flow stool antigen test can be used as an alternative to breath test for H. pylori infection diagnosis especially in developing countries.

Human herpesvirus 8 (HHV-8), the etiological agent of Kaposi's sarcoma (KS), is endemic in parts of the sub-Saharan, and KS has increased concomitantly with the HIV/AIDS epidemic. In Mozambique (MZ), no data concerning HHV-8 infection was available, thus the main of this work was to investigate, for the first time, the presence of HHV-8 infection in Maputo, MZ. Latent and lytic HHV-8-specific antibodies were assessed in blood samples from 189 individuals from the Central Hospital of Maputo, MZ, using "in-house" immunofluorescence assays conducted in São Paulo, Brazil. The results obtained were analyzed according to socio-demographic and clinical variables using the Chi-square test and logistic regression. An HHV-8 seropositivity of 1.8% and 9.7% was detected among 57 medical students and 31 individuals from the staff, respectively, in contrast to 16.4% detected among 67 out-patients. Concerning 34 hospitalized patients from the Dermatology Unit, 47.1% were HHV-8-seropositive overall, while the rate was 85.7% among KS patients. The present survey, conducted in Maputo, MZ, demonstrates great variation in HHV-8 infection frequencies depending on the group analyzed and epidemiological variables. An association between HHV-8 seropositivity and male gender (OR 5.72), the central origin of patients (OR 5.33), blood transfusions (OR 3.25), and KS (OR 24.0) was detected among hospitalized patients, and primary school (OR 7.18) and HIV-1 infection (OR 8.76) among out-patients.