An endoscope is a long, thin fiber optic tube with a small camera at the end, that is passed into your body directly to observe an internal organ or tissue in detail through a natural opening such as your mouth. It can also be used to carry out other tasks take biopsy samples & minor surgery.

During an (A) Upper gastric endoscopy or OGD, an endoscope is easily passed through the mouth and throat and into the esophagus, allowing the doctor to view the esophagus, stomach, and upper part of the small intestine. It is done under sedation.
Similarly, endoscopes can be passed into the large intestine (colon) through the rectum to examine this area of the intestine. This procedure is called sigmoidoscopy or (B) Colonoscopy depending on how far up the colon is examined.

Alternatively, they can be inserted into small incisions, for instance, in the knee or abdomen. Surgery completed through a small incision and assisted with special instruments, such as the endoscope, is called keyhole surgery/laparoscopy. Endoscopes have a wide range of use in many regions of the human body both for diagnosis & treatment


Common Disorders that Require Gastroscopy(Upper Endoscopy/OGD)

• Investigate symptoms. An endoscopy can help determine what’s causing digestive signs and symptoms, such as heartburn, nausea, vomiting, abdominal pain, difficulty swallowing and gastrointestinal bleeding.
• Diagnose. An endoscopy offers an opportunity to collect tissue samples (biopsy) to test for diseases and conditions that may be causing anemia, bleeding, inflammation or diarrhea. It can also detect some cancers of the upper digestive system.
• Treat. Special tools can be passed through the endoscope to treat problems in your digestive system. For example, an endoscopy can be used to burn a bleeding vessel to stop bleeding, widen a narrow esophagus, clip off a polyp, or remove a foreign object.

Risks to the Procedure

An endoscopy is a very safe procedure. Rare complications include:
  • Bleeding. Your risk of bleeding complications after an endoscopy is increased if the procedure involves removing a piece of tissue for testing (biopsy) or treating a digestive system problem. In rare cases, such bleeding may require a blood transfusion.
  • Infection. Most endoscopies consist of an examination and biopsy, and risk of infection is low. The risk of infection increases when additional procedures are performed as part of your endoscopy. Most infections are minor and can be treated with antibiotics. Your provider may give you preventive antibiotics before your procedure if you are at higher risk of infection.
  • Tearing of the gastrointestinal tract. A tear in your esophagus or another part of your upper digestive tract may require hospitalization, and sometimes surgery to repair it. The risk of this complication is very low — it occurs in an estimated 1 of every 2,500 to 11,000 diagnostic upper endoscopies. The risk increases if additional procedures, such as dilation to widen your esophagus, are performed.
  • A reaction to sedation or anesthesia. Upper endoscopy is usually performed with sedation or anesthesia. The type of anesthesia or sedation depends on the person and the reason for the procedure. There is a risk of a reaction to sedation or anesthesia, but the risk is low.

After discussing the risks of the gastroscopy/OGD with you, your health provider will ask you to sign a consent form giving permission for the procedure.

Symptoms to watch for after your Endoscopy include:

  • Fever
  • Chest pain
  • Shortness of breath
  • Bloody, black, or very dark-colored stool
  • Difficulty swallowing
  • Severe or persistent abdominal pain
  • Vomiting, especially if your vomit is bloody or looks like coffee grounds

Call your provider immediately or go to an emergency room if you experience any of these symptoms.

How to Prepare for the Procedure

Your provider will give you specific instructions to prepare for your endoscopy. You may be asked to:

  • Fast before the endoscopy. You’ll typically need to stop eating solid food for eight hours and stop drinking liquids for four hours before your endoscopy. This is to ensure your stomach is empty for the procedure.
  • Stop taking certain medications. You’ll need to stop taking certain blood-thinning medications in the days before your endoscopy, if possible. Blood thinners may increase your risk of bleeding if certain procedures are performed during the endoscopy. If you have ongoing conditions, such as diabetes, heart disease or high blood pressure, your provider will give you specific instructions regarding your medications.
  • Tell your provider about all the medications and supplements you’re taking before your endoscopy.

Plan ahead for your recovery

Most people undergoing an upper endoscopy will receive a sedative to relax them and make them more comfortable during the procedure. Plan ahead for your recovery while the sedative wears off. You may feel mentally alert, but your memory, reaction times and judgment may be impaired. Find someone to drive you home. You may also need to take the day off from work. Don’t drive or make important personal or financial decisions for 24 hours.

During an Endoscopy

During an upper endoscopy procedure, you’ll be asked to lie down on a table on your back or on your side. As the procedure gets underway:

  • Monitors often are attached to your body. This allows your healthcare team to monitor your breathing, blood pressure, and heart rate.
  • You may receive a sedative medication. This medication, given through a vein in your forearm, helps you relax during the endoscopy.
  • An anesthetic may be used in your mouth. An anesthetic spray numbs your throat in preparation for inserting the long, flexible tube (endoscope). You may be asked to wear a plastic mouth guard to hold your mouth open.
  • Then the endoscope is inserted into your mouth. Your provider may ask you to swallow as the scope passes your throat. You may feel some pressure in your throat, but you shouldn’t feel pain.
  • A tiny camera at the tip of the endoscope transmits images to a video monitor in the exam room to identify any pathologies that may be present and possibly collect a tissue sample or remove a polyp. This may be done by passing special small surgical tools through the endoscope
  • Gentle air pressure may be fed into your esophagus to inflate your digestive tract for ease of examination. You may feel pressure or fullness from the added air.

When the exam is finished, the endoscope is slowly retracted through your mouth. An endoscopy typically takes 15 to 30 minutes.

After the Gastroscopy/OGD

You’ll be taken to a recovery area to sit or lie quietly after your endoscopy. You may stay for an hour or so. During this time, your healthcare team can monitor you as the sedative begins to wear off. You may have something light once you’re fully awake. Once you’re at home, you may experience some mildly uncomfortable symptoms after endoscopy, such as:

  • Bloating and gas
  • Cramping
  • Sore throat

These signs and symptoms will improve with time. If you’re concerned or quite uncomfortable, call your healthcare provider. Take it easy for the rest of the day after your endoscopy. After receiving a sedative, you may feel alert, but your reaction times are affected and judgment is delayed.


Depending on what is visualized during the procedure, your health provider may discuss the results or request additional investigation if a tissue sample (biopsy) was collected, from the laboratory. Ask your provider when you can expect the results of your endoscopy.


Common Disorders that Require Colonoscopy


  • Investigate intestinal signs and symptoms. A colonoscopy can help your doctor explore possible causes of abdominal pain, rectal bleeding, chronic diarrhea, and other intestinal problems. A tissue sample (biopsy) may be collected to investigate further at the lab.
  • A colonoscopy is used to look for changes, such as swollen, irritated tissues, polyps, or screen for cancer, in the large intestine (colon) and rectum.
  • Treat an issue. Sometimes, a colonoscopy may be done for treatment purposes, such as placing a stent, removing an object from your colon, or clipping a polyp.

Risks to the Procedure

A colonoscopy poses few risks. Rarely, complications of a colonoscopy may include:

  • A reaction to the sedative used during the exam
  • Bleeding from the site where a tissue sample (biopsy) was taken or a polyp or other abnormal tissue was removed
  • A tear in the colon or rectum wall (perforation)

After discussing the risks of colonoscopy with you, your health provider will ask you to sign a consent form giving permission for the procedure.

How to Prepare for the Procedure

Before a colonoscopy, you’ll need to clean out (empty) your colon. Any residue in your colon may make it difficult to get a good view of your colon and rectum during the exam. To empty your colon, your doctor may ask you to:

  • Follow a special diet the day before the exam. Typically, you won’t be able to eat solid food the day before the exam. Drinks may be limited to clear liquids — plain water, tea, and coffee without milk or cream, broth, and carbonated beverages. Avoid red liquids, which can be mistaken for blood during the colonoscopy. You may not be able to eat or drink anything after midnight the night before the exam.
  • Take a laxative. Your doctor will usually recommend taking a prescription laxative, usually in a large volume in either pill or liquid form. In most instances, you will be instructed to take the laxative the night before your colonoscopy, or you may be asked to use the laxative both the night before and the morning of the procedure.
  • Adjust your medications. Remind your doctor of your medications at least a week before the exam — especially if you have diabetes, high blood pressure, or heart problems or if you take medications or supplements that contain iron.

Also tell your doctor if you take aspirin or other medications that thin the blood, such as warfarin (Coumadin, Jantoven); newer anticoagulants, such as dabigatran (Pradaxa) or rivaroxaban (Xarelto), used to reduce risk of blot clots or stroke; or heart medications that affect platelets, such as clopidogrel (Plavix).

You may need to adjust your dosages or stop taking the medications temporarily.

During the Procedure

  • During a colonoscopy, you’ll wear a gown, but likely nothing else. Sedation or anesthesia is usually recommended. In most cases, the sedative is combined with pain medication given directly into your bloodstream (intravenously) to lessen any discomfort.
  • You’ll begin the exam lying on your side on the exam table, usually with your knees drawn toward your chest. The doctor will insert a colonoscope into your rectum.
  • The scope — which is long enough to reach the entire length of your colon — contains a light and a tube (channel) that allows the doctor to pump air, carbon dioxide, or water into your colon. The air or carbon dioxide inflates the colon, which provides a better view of the lining of the colon.
  • When the scope is moved or air is introduced, you may feel stomach cramping or the urge to have a bowel movement.
  • The colonoscope also contains a tiny video camera at its tip. The camera sends images to an external monitor so that the doctor can study the inside of your colon.
  • The doctor can also insert instruments through the channel to take tissue samples (biopsies) or remove polyps or other areas of abnormal tissue.

A colonoscopy typically takes about 30 to 60 minutes.

After the Colonoscopy

After the exam, it takes about an hour to begin to recover from the sedative. You’ll need someone to take you home because it can take up to a day for the full effects of the sedative to wear off. Don’t drive or make important decisions or go back to work for the rest of the day.

You may feel bloated or pass gas for a few hours after the exam, as you clear the air from your colon. Walking may help relieve any discomfort.

You may also notice a small amount of blood with your first bowel movement after the exam. Usually, this isn’t cause for alarm. Consult your doctor if you continue to pass blood or blood clots or if you have persistent abdominal pain or a fever. While unlikely, this may occur immediately or in the first few days after the procedure, but may be delayed for up to 1 to 2 weeks.


Negative Result

  • A colonoscopy is considered negative if the doctor doesn’t find any abnormalities in the colon. Your doctor may recommend that you have a screening colonoscopy depending on your age at certain intervals or if at high risk
  • If there was a residual stool in the colon that prevented a complete examination of your colon, your doctor may recommend a repeat colonoscopy. How soon will depend on the amount of stool and how much of your colon was able to be seen? Your doctor may recommend a different bowel preparation to ensure that your bowel is completely emptied before the next colonoscopy.

Positive Result

A colonoscopy is considered positive if the doctor finds any polyps or abnormal tissue in the colon.

Most polyps aren’t cancerous, but some can be precancerous. Polyps removed during colonoscopy are sent to a laboratory for analysis to determine whether they are cancerous, precancerous, or noncancerous.

Depending on the size and number of polyps, you may need to follow a more rigorous surveillance schedule in the future to look for more polyps.

If you have a polyp or other abnormal tissue that couldn’t be removed during the colonoscopy, your doctor may recommend a repeat exam with a gastroenterologist who has special expertise in removing large polyps, or surgery.

Biopsy Result

Your healthcare provider may take a tissue sample (biopsy) during the procedure depending on what was visualized. This tissue is then examined under a microscope and investigated further by a pathologist at a lab to help identify the cause of your symptoms.