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How does a gastroscopy work?

Gastroscopy (also called upper gastrointestinal endoscopy) is a procedure used to examine the upper section of the digestive system (i.e. the throat, esophagus and stomach). This is considered as a safe and minimally invasive procedure. One of the greatest areas to look for qualified specialists to assist you with gastroscopy is Singapore where the said procedure is one of the most frequently sought medical procedures. Visit to access a listing of top-notch Singaporean experts.

In Singapore and in most countries, gastroscopy is one of the procedures used to screen and diagnose gastric and stomach cancers. Also, this procedure is used to see the sources of symptoms experienced by a patient. Most of the time, a family physician or general practitioner will advise for gastroscopy to see reasons for the following list of symptoms:

  • Stomach discomfort, heartburn, or indigestion that does not go away even after taking medication
  • Continued experience of nausea, vomiting, or both
  • Throwing-up blood
  • Having bowel that are sticky and dark like tar (which may be caused by blood in the stomach)
  • Swallowing issues or swallowing discomfort
  • Unexplained weight loss
  • Iron deficiency anemia
  • Chest pains not caused by heart conditions


Aside for conducting examination of the upper digestive tract due to symptoms, gastroscopy is also used to perform the following:

  • Biopsy or taking a small tissue sample to be examined further
  • Stop an ulcer from bleeding
  • To get rid of polyps or growths that develop on the linings of the esophagus, stomach or small intestines

The instrument used in gastroscopy is called the gastroscope. The gastroscope is a flexible tube (as thin as a finger) that has a tiny light and a camera connected to the end of it. The videos or images captured by the camera are received by a computer screen which enables the doctor to view the insides of the upper digestive tract. By inserting tools like tiny pincers, the tube can be used to collect tissue samples. It can also be used to remove liquids and air. Due to advancements in technology, gastroscopes nowadays are capable of producing high-definition videos for a more clear picture of the insides of the body part examined.


Before the procedure, an initial consultation with the specialist is to be expected where certain information such as your symptoms and medical history will be discussed. Your doctor will also explain the procedure including the details on the medications (e.g. local anesthesia or sedation) you can use to relax during the procedure as well as any possible risks. In addition, you should discuss with your doctor any allergies or other medical concerns you may have. Once established that you are a candidate for a gastroscopy, a schedule will be made. Here are a few tips to help you prepare for your gastroscopy appointment:

  • Before the procedure, you might need to temporarily cease taking your prescriptions
  • Prior to the treatment, you shouldn’t eat for six to eight hours and you shouldn’t drink anything for two to three hours
  • It is ideal to plan for someone to pick you up from the procedure, drive you home, and stay with you for at least a day
  • On the day of the your appointment, wear loose and comfortable clothes


On the day of your appointment, preliminaries such as a quick check on you, sedation, etc. will take place to prepare you for the procedure. During gastroscopy, the gastroscope will be inserted into your mouth and gently pushed down your throat. Expect to be asked by the doctor to swallow a few times to aid the gastroscope’s movement inside your mouth and throat. This is where the sedative is useful as it will suppress any gag reaction and pain felt during insertion.


From the mouth, the gastroscope will be guided by the doctor along your upper digestive tract to be able to examine the esophagus and the stomach. During the process, the doctor will rotate the gastroscope’s camera tip around to see different angles as it moves along the way. Air will also be pumped from the instrument to inflate your stomach for a better view of its insides. The video images from the camera of the gastroscope are viewed on a monitor. Depending on your case, samples of your tissue may also be taken as the procedure progresses. The procedure is relatively painless, but it is important to note that you have the option to stop any time. 


When the doctor is satisfied with what he or she has seen, the gastroscope will then be carefully removed from your body. And the procedure is over. 

Typically, gastroscopy ought to take 15 to 45 minutes to complete. 


You will be sent to a recovery room once the gastroscopy is over. As soon as you are well enough to do so, you should be able to return home.  You will need someone to drive you home and stay with you for 24 hours if you’ve had sedation. Until your gag reflex returns, you are not permitted to eat or drink anything to prevent you from choking. Also, for a few days, swallowing could cause you to have a sore throat and discomfort. If you haven’t received any more instructions, you can resume your regular diet and activities. Refrain alcohol intake and operating machineries if you have had sedation. 


Serious complications from gastroscopy are uncommon, and the procedure is considered as safe. Although complications are exceedingly rare, the stomach or bowel could be perforated. When a surgical operation, like the excision of polyps or a biopsy, is involved in the gastroscopy, this is more likely to happen. If a blood vessel or the lining of the digestive tract is ruptured unintentionally, bleeding may result. Additional surgery might be required to fix such damage. In extremely rare situations, sedation or infection-related problems could arise. If you experience any of the following, get in touch with your doctor right away:

cold or fever

  • Injection site irritation with redness, edema, bleeding, or other discharge
  • Vomiting, nausea, or stomach pain
  • Bloody, dark, or tarry stools
  • difficulty swallowing
  • worsening throat or chest ache
  • Depending on your circumstances, your healthcare practitioner may give you different directions.


Gastrohealth Clinic – Dr Bhavesh Doshi | Gastroenterologist | Colonoscopy Singapore


6A Napier Rd, #03-370 Gleneagles Hospital Annexe Block, Singapore 258500


+65 6355 5773