If you've had long-term stomach issues, this test can provide a crucial answer. It checks your blood for IgG antibodies, the "memory" antibodies your body produces after a past or long-term exposure to the H. pylori bacteria. A positive result indicates you have been exposed to this ulcer-causing bacteria at some point, even if you no longer have symptoms. It is essential for investigating the cause of chronic gastritis or peptic ulcers. This simple blood draw provides the 'historical' evidence your doctor needs to understand your symptoms.