Your doctor will probably suspect gastritis after checking your symptoms and medical history and performing an exam-you may have tests to identify the exact cause. E. g. a blood test to check for the presence of H. pylori antibodies. A positive test means you've come in contact with the bacteria at some point, but don't necessarily have a current infection; you might also take blood tests for anemia, caused by stomach bleeding; a breath test to show whether you're currently infected with H. pylori bacteria; tests on stool to check for H. pylori in your faeces. A positive test suggests current infection. Your doctor may also test for blood in your faeces-a sign of stomach bleeding that gastritis can cause.
Attribution: Avallain