How long does gastroscopy usually take?

Do ordinary gastroscopy generally takes about 15 minutes, do painless gastroscopy takes about 30 minutes, but the condition is different, the time may vary. In addition, the day before gastroscopy after ten o'clock in the evening patients should fast, ban water, to prevent food residue in the stomach, resulting in gastroscopy can not see whether there are lesions in the gastric mucosa, so affect the results. And painless gastroscopy after one to two hours do not eat.