RESUMEN
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.
Asunto(s)
Antígenos Bacterianos/análisis , Heces/química , Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/inmunología , Adolescente , Adulto , Anciano , Heces/microbiología , Femenino , Helicobacter pylori/aislamiento & purificación , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto JovenRESUMEN
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 percent; 95 percent CI: 75.7-95.5 percent), and six false-negative; and in the H. pylori-negative group 42 presented negative results (specificity 87.5 percent; 95 percent CI: 74.7-95.3 percent), and six false-positive, showing a substantial agreement (Kappa Index = 0.75; p < 0.0001; 95 percent 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 percent (95 percent CI: 75.7-95.5 percent), and 42 patients with negative stool antigen test were H. pylori-negative, the NPV of the stool antigen test was 87.5 percent (95 percent CI: 74.7-95.3 percent). 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.
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 por cento; 95 por cento IC: 75.7-95.5 por cento), com seis falso-negativos; e no grupo H. pylori negativo, 42 apresentaram resultados negativos (especificidade de 87,5 por cento; 95 por cento IC: 74.7-95.3 por cento), com seis falso-positivos, mostrando concordância substancial (índice Kappa = 0.75; p < 0.0001; 95 por cento 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 por cento (95 por cento IC: 75.7-95.5 por cento), e 42 pacientes com teste de antígeno fecal negativo eram H. pylori negativos, com VPN de 87,5 por cento (95 por cento IC: 74.7-95.3 por cento). 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.
Asunto(s)
Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Antígenos Bacterianos/análisis , Heces/química , Infecciones por Helicobacter/diagnóstico , Helicobacter pylori/inmunología , Heces/microbiología , Helicobacter pylori/aislamiento & purificación , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto JovenRESUMEN
OBJECTIVES: To validate C/T(-13910) polymorphism associated with primary hypolactasia for clinical practice. DESIGN AND METHODS: Lactose breath test and PCR-RFLP for the C/T(-13910) polymorphism were performed. RESULTS: Twenty-seven of 28 patients with genotype CC had positive breath tests; all twenty-two patients with genotypes CT or TT had negative breath tests. Agreement of tests was high (p<0.0001; Kappa Index 0.96). CONCLUSION: C/T(-13910) polymorphism detection may be a new tool for primary hypolactasia diagnosis.
Asunto(s)
Lactasa/genética , Intolerancia a la Lactosa/genética , Polimorfismo de Nucleótido Simple/genética , Adulto , Anciano , Pruebas Respiratorias/métodos , Femenino , Variación Genética/genética , Humanos , Intolerancia a la Lactosa/diagnóstico , Prueba de Tolerancia a la Lactosa/métodos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodosRESUMEN
The purpose of this study was to verify whether the presence of any of the Helicobacter pylori cagPAI genes or segments--cagA, cagA promoter, cagE, cagM, tnpB, tnpA, cagT and the left end of the cag II (LEC) region--would be a useful marker for the risk of peptic ulcer disease development. H. pylori DNA extracted from positive urease tests of 150 peptic ulcer patients and 65 dyspeptic controls was analysed by PCR. Duodenal ulcers were present in 110, gastric ulcers in 23 and both gastric and duodenal ulcers in 17 patients. A significant association (P <0.001) was found between a conserved cagPAI and peptic ulcer disease (34 %). The positivity of the cagA gene varied according to the region of the gene that was amplified. The region near to the promoter was present in almost all of the H. pylori isolates (97.2 %). The segment from nt 1764 to 2083 and the extreme right end were frequently deleted in the isolates from the controls (P <0.01). The positivity of the promoter region of cagA and cagT, cagE, cagM and LEC showed a significant difference between the isolates from peptic ulcer patients and from the controls (P <0.01). Patients usually had moderate gastritis; however, the intensity of the active inflammation was higher in the peptic ulcer group (P <0.001). cagT, cagM, LEC and the right end terminus of the cagA-positive H. pylori isolates were associated with a 27-fold, 8-fold, 4-fold and 4-fold risk of peptic ulcer disease, respectively, and may be useful markers to identify individuals at higher risk of peptic ulcer disease development in Brazil.