A blood test for H. pylori is not always accurate; a positive blood test result means that there is or has been a H. pylori infection, which includes cases where there has been a H. pylori infection that has now been cured. If you want to check whether you have H. pylori infection now, you also need to use a breath test and gastroscopy to determine this. A blood test for H. pylori is used to determine whether or not the body is infected with H. pylori by checking for H. pylori antibodies in the blood. If the blood test is negative, the organism has not been and is not currently infected with H. pylori; if the blood test is positive, the organism may be currently infected with H. pylori or the organism may have been infected with H. pylori. Breath test is done by taking carbon 13 or 14 labeled urea and blowing into a test bag after 15 minutes, which indirectly reflects the presence of H. pylori in the stomach by detecting whether the gas in the bag contains carbon 13 or 14 labeled carbon dioxide. Gastroscopy can reflect whether H. pylori is infected or not by taking part of gastric mucosa for rapid urease test under gastroscope. If H. pylori is contained in this piece of gastric mucosa, the reagent can be discolored by secretion of urease by H. pylori; otherwise, the reagent will not be discolored. H. pylori can also be detected by staining the gastric mucosa tissue under gastroscopy. To check for H. pylori infection, please follow your doctor’s instructions.