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HF 5160

24-Hour pH Monitoring and Impedance Study

pH monitoring is used to diagnose esophageal reflux. A small flexible tube is passed through your nose into your esophagus. The nurse connects the tube to a small recording device that measures the acid present in your esophagus. You will carry this recording device with you for 22-24 hours and record meal periods, sleeping periods, and reflux symptoms. The recorder measures how often acid may move into the esophagus from the stomach and if this relates to your symptoms.

Getting Ready

  • This test can be done either on or off acid blocking medicine. Follow your doctor's recommendations whether to stop your medicines for testing. Only stop your acid blocking medicine if your doctor advises you to do so.

  • No solid food after midnight the night before your exam. You may continue drinking clear liquids until 4 hours before you arrive. 

  • Diabetic medicines (oral and insulin) will need to be adjusted for the time you’re not eating as normal. Please discuss this with your primary doctor. 

Day of Procedure

  • Stop drinking liquids 4 hours before you arrive. You may take medicine with sips of water up until 2 hours before your appointment. 

  • Plan to be here about 45 minutes.

  • Your nose will be numbed, and a small tube will be inserted through your nose and into your esophagus.

  • After the tube is placed, you will be asked to eat and drink normally. If you have noticed any foods that make your symptoms worse, please have them available at home to eat during your test.

  • The nurse will instruct you on use of the recorder and the diary. All of your questions will be answered during your visit.

  • You must handle the data recorder with care. Do not drop or bang it. You may not shower/bathe or get the recorder wet. 

Return of Recorder and Probe Removal

At the end of the study period, you will return to the clinic for probe removal and return the recording device as directed. Please bring your diary with you as well. 

After the Test 

Results from your diary and the pH recorder will be entered into a computer. Please allow 1-2 weeks for the final report to be available for your doctor to review. 

How to Contact Us 

UW Health Digestive Health Center

750 University Row 

Madison, WI 

(608) 890-5000 

(855) 342-9900 

UW Health at The American Center 

4602 Eastpark Blvd. 

Madison, Wisconsin 53718

(608) 242-2898

(608) 440-6300

University of Wisconsin Hospital & Clinics 

GI Procedure Clinic 

600 Highland Avenue Madison, WI

(608) 263-8097 

(800) 323-8942

If you are a patient receiving care at UnityPoint – Meriter, Swedish American or a health system outside of UW Health, please use the phone numbers provided in your discharge instructions for any questions or concerns.