A C14 greater than 50 is not necessarily positive. The normal value of C14 is below 100 (dpm/mmol CO₂), if it is less than 100 (dpm/mmol CO₂), it is negative, and if it is higher than this value, it is positive, so C14 is greater than 50 (dpm/mmol CO₂) cannot be judged as positive. After infection with H. pylori, H. pylori breaks down the urea on the surface of the gastric mucosa and produces carbon dioxide that enters the lungs with the bloodstream. The C14 breath test consists of a C14-labeled urea capsule with a certain amount of radioactivity, which the patient is allowed to take, and determines the existence of an infection by detecting carbon dioxide containing C14. The C1 breath test is a commonly used diagnostic tool for H. pylori, with a normal C14 value of less than 100 (dpm/mmol CO₂) being negative and greater than 100 (dpm/mmol CO₂) being positive.The C14 breath test only suggests the presence of a H. pylori infection, and the value does not indicate the severity of the condition or the prognosis of the disease. Generally speaking, C14 greater than 50 (dpm/mmol CO₂) cannot be considered as positive for H. pylori, and it needs to be greater than 100 (dpm/mmol CO₂) to be judged as positive, so it is recommended to consult your doctor in conjunction with your own symptoms.