Knowledge of the cagA status of Helicobacter pylori infection could be relevant for the treatment and prevention of possible complications of infection. This goal can be achieved using serology since CagA is highly immunogenic. The aim of this study was to correlate the presence of the cagA gene detected by polymerase chain reaction (PCR) with the presence of serum antibodies against the CagA protein using a recently available commercial immunoblotting assay, the Helico Blot 2.1 kit. Considering the results obtained by PCR, Helico Blot 2.1 presented sensitivity, specificity, and positive and negative predictive values for CagA status of 97.4%, 87.7%, 80.9% and 98.5%, respectively.