Helicobacter pylori Infection among Patients Seen at Federal Medical Centre Asaba, Delta State: A Comparison of Serological and Faecal Antigen Testing Methods

Abstract

Background: Helicobacter pylori is a Gram-negative, microaerophilic bacterium that has been established as the primary aetiological agent responsible for chronic gastritis and peptic ulcer disease. Aim: This study aimed to compare the diagnostic performance of serological testing with faecal antigen testing for the diagnosis of H. pylori infection in subjects attending Federal Medical Centre, Asaba. Accurate diagnosis of infection is important for effective management and control. Methodology: A comparison of the performance of two diagnostic test methods, serology and stool antigen testing, for Helicobacter pylori infection was conducted among 397 patients using a prospective cross-sectional study design. Blood and fresh stool samples were collected from eligible patients after consent. Serum samples were tested for H. pylori antibodies using a serological method, whereas stool samples were tested for H. pylori antigen. The stool antigen method was used as the reference method for assessing the diagnostic performance of serology. Sensitivity, specificity, positive predictive value, negative predictive value, and the level of agreement between the two methods were also analysed. Results: The age distribution of participants was similar across genders, with a mean age of approximately 38 years. Serology and stool antigen testing showed similar positivity rates of 43.07% and 42.57%, respectively. Using stool antigen testing as the reference method, the serological test showed a sensitivity of 93.5% and specificity of 94.3%, with a positive predictive value (PPV) of 92.4% and a negative predictive value (NPV) of 95.1%. However, Cohen’s kappa analysis showed 0.877 (95% CI:0.83-0.92) indicating almost perfect agreement. Conclusion: The study demonstrated that the serological method showed high diagnostic performance compared with stool antigen testing and may be useful as a screening method for H. pylori infection when the serology result is negative. However, stool antigen testing remains useful for confirming active infection because it detects active infection rather than past exposure.