Abstract
Helicobacter pylori is an infectious agent linked to significant gastric pathologies, which makes it a public health concern. The enzyme-linked immunosorbent assay (ELISA) is widely used for epidemiological studies and for investigating virulence factors like the cagA gene. Due to the varying antigenic profiles of bacterial strains across different populations, the local validation of serological tests is essential. This study aimed to evaluate the performance of two commercial serological tests - the MyBiosource HP-CagA-IgG ELISA kit and the Sunlong Human IgG (CagA-IgG) ELISA kit - in detecting the cagA virulence factor and to assess its prevalence in bacterial isolates from a population in the southwest region of Bahia. A total of 88 individuals were enrolled, and 34 tested positive for the cagA factor via real-time PCR. After establishing customized cutoff points, the MyBiosource kit demonstrated a sensitivity of 55.88%, specificity of 50%, and accuracy of 52.22%, while the Sunlong kit showed a sensitivity of 70.59%, specificity of 60%, and accuracy of 64.29%. Despite these results, neither test met satisfactory performance standards, with sensitivity below 75% and specificity ranging from 50 to 60%. The overall prevalence of H. pylori infection was 56.8%, with a cagA prevalence of 68% among positive cases. Further investigations using additional commercial tests are recommended to enhance diagnostic outcomes for this population.