Serologic Detection of Helicobacter pylori Infection and the Required Cautions

Helicobacter pylori, as an etiologic cause of peptic ulcers and gastric cancer, should be tested and treated. The true state of infection can only be detected by isolation of gastric biopsies through the invasive method of gastroscopy. However, there are several non-invasive methods for detection of infection, the most common of which is serology.
Here we have evaluated the efficacy of two commonly used commercial IgG-based ELISA kits (Kit-1 and Kit-2) against the endoscopy (biopsy)-based methods of rapid urease test (RUT) and bacterial culture. Our study population included 754 subjects categorized as having: 1) nonulcer dyspepsia (NUD, N=485), 2) peptic ulcer disease (PUD, N=65), and 3) gastric cancer (GC, N=204).
The rates of agreement between the results obtained by Kit-1, Kit-2 and both kits with culture/RUT were 62.4% (318 of 500, P=0.0001), 74.4% (183 of 246, P96% and >99%) were significantly reduced (Kit-1: 94.4% and 40.3%; Kit-2: 86.5% and 71%) for the Iranian population.
Our data raises questions regarding the accuracy of commercial IgG-based ELISA kits for the detection of H. pylori infection. Therefore, caution should be practiced when such tests are used as the sole basis of medical decision making.