- Barium x ray
After fasting for 12 hours, you will drink a thick liquid called barium, which coats the inside of the stomach, making it show up on the x ray. Normally, the stomach will be empty of all food after 12 hours of fasting. If the x ray shows food in the stomach, gastroparesis is likely. If the x ray shows an empty stomach but the doctor still suspects that you have delayed emptying, you may need to repeat the test another day. On any one day, a person with gastroparesis may digest a meal normally, giving a falsely normal test result.
- Radioisotope gastric-emptying scan
You will eat food that contains a radioisotope, a slightly radioactive substance that will show up on the scan. The dose of radiation from the radioisotope is small and not dangerous. After eating, you will lie under a machine that detects the radioisotope and shows an image of the food in the stomach and how quickly it leaves the stomach. Gastroparesis is diagnosed if more than half of the food remains in the stomach after 2 hours.
- Gastric manometry
This test measures electrical and muscular activity in the stomach. The doctor passes a thin tube down the throat into the stomach. The tube contains a wire that takes measurements of the stomach's electrical and muscular activity as it digests liquids and solid food. The measurements show how the stomach is working and whether there is any delay in digestion.