If you have symptoms of heartburn or throat clearing, cough, and voice change, your physician may want to determine the amount of acid (the pH) that is getting into the back of your throat or your pharynx. This test is called ambulatory monitoring because you go home and go about your usual daily routine while you’re being monitored.

A small (1.5 millimeter) catheter is inserted through your nose and down the back of your throat. The tube is taped in place on your nose and has a cord that is attached to a receiver and has a portable recorder. You wear the recorder in a pouch that has a strap that goes around your waist or neck.

How Should You Prepare for The Procedure?

  • Do not eat or drink anything for two hours prior to the test. This also includes chewing gum, mints and hard candies.
  • You may take certain necessary medications with a small sip of water up to two hours before the test. Please check with your doctor regarding any medications you take.
  • You will be asked to sign an informed consent and provide information regarding allergies, medicines you are now taking, existing medical conditions and previous surgeries.
  • You may also wish to shower or bathe before your appointment, as you will be unable to do so for 24 hours during the duration of the test.

Unless instructed otherwise by your physician:

  • You need to stop Nexium, Protonix, Prilosec, Prevacid or Aciphex 14 days prior to testing.
  • You need to stop Tagamet, Zantac, Axid or Pepcid 72 hours prior to testing.
  • You need to stop Bentyl, Carafate and Reglan 72 hours prior to testing.
  • You need to stop antacids (i.e. Tums, Maalox and Mylanta) 24 hours prior to testing.

What Can You Expect During The Procedure?

  • The test will last for 24 hours during which you will be asked to keep a diary of your activities and your symptoms – when you eat, lie down, take medications, and when you have symptoms such as heartburn, chest pain, coughing, voice change, throat clearing, etc. It is very important to be accurate when keeping your diary!
  • No sedatives will be given for this procedure; however, your nostril will be numbed with an anesthetic gel to allow for easier placement of the catheter.
  • A very small, flexible catheter (about the size of a spaghetti noodle) is inserted through your nostril and advanced to the back of your throat.
  • The catheter will be attached to a transmitter and has a portable recorder that measures your reflux activity for 24 hours.
  • Eat the foods you would normally eat per the instruction sheet.
  • You may drink beverages listed on the instruction sheet with meals; however, you may only have water between meals.
  • Do not chew gum, eat hard candies, or have mints during the test.
  • Do not shower or bathe. Do not get the recorder and transmitter wet or expose them to excessive moisture; they are not waterproof. Doing so may damage the equipment as well as provide incorrect or inaccurate data.
  • After 24 hours you will need to return to the Endoscopy department. You will need to remember to bring your diary!

What Happens After The Procedure?

  • You may resume your normal daily activities.
  • Please schedule a follow-up visit with your doctor to discuss the results of your test.

Contact Us

If you have questions or are looking for more information, please complete the form below and we will contact you.


Thank you for contacting the Memorial Hermann Digestive Health. We have received your inquiry, and a team member will contact you soon.

If you need more immediate assistance, please call us at (713) 222-2273.

If you are experiencing a medical emergency, call 911 or go to the nearest emergency room.