Background: Approximately 89% of gastric cancers are attributable to H. pylori infection, however, only 1 in 5 patients survive longer than 5 years after diagnosis. Evidence has shown that screening and eradication of H. pylori in young adults would be cost-effective and could prevent 1 gastric cancer in every 4 to 6 cases. Diagnostic tests used to detect Helicobacter pylori are either invasive or noninvasive methods. These tests have varying sensitivity and specificity, having about 90% accuracy in the diagnosis of H. pylori infection in clinical practice. Aim: This study aims at detecting Helicobacter pylori using antibody-antigen, stool antigen and polymerase chain reaction (PCR) and to compare the infection rate among the different diagnostic techniques. Methodology: This was a cross-sectional study. The participants included attendants to tertiary and private hospitals in Port Harcourt metropolis for medical treatment. Blood and stool samples were collected from one hundred and eighty (180) subjects aged 1 to 60 years and above. Ethical approval for the study was obtained from the Rivers State University Teaching Hospital Ethics Committee. Convenience sampling technique was deployed. Samples were collected from subjects who consented to the study. All samples collected were analyzed in Medical Microbiology Laboratory, Rivers State Teaching Hospital and subsequently, molecular analysis was carried out. Results: The blood antibodies test (serology) method shows a greater number of positive cases (43.9%) than stool antigen method (8.3%). Also, out of the 75% stool antigen positive samples, subjected to more specific PCR, only 25% were positive. There was a significant difference (p-value of <0.001) in sensitivity between antigen and serology, there was also a significant difference (p-value of <0.025) between antigen and PCR result outcomes. Conclusion: The study has shown that there is a notable variation in the diagnosis of H pylori among the laboratory techniques used.