HF 8300

24-Hour pH Monitoring and Impedance Study on Acid Medicines

We use pH monitoring to diagnose esophageal reflux. This Health Facts for You will tell you how the study works, how to get ready for this study and when to expect your results. Read these instructions carefully before your study.

How the Study Works

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

Getting Ready

Acid blocking medicine: You do not need to change your current medicines for your test.

Diet: No solid food after midnight the night before your study. You may keep drinking clear liquids until 4 hours before you arrive.

Diabetic medicines: You may need to adjust your oral medicine and insulin for the time you’re not eating as normal. Please discuss this with your primary doctor.

Day of Procedure

  • You will not need someone to drive you.

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

  • We will numb your nose and insert a small tube through your nose and into your esophagus.

  • Once the tube is in place, we will ask you to eat and drink normally. If you have noticed any foods that make your symptoms worse, please have them at home to eat during your test.

  • We will teach you how to use the recorder and the diary and answer any questions you have.

Caring for the Recorder

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

You will return to the clinic when the study is complete. At this visit, you will have the probe removed and you will return the device as directed. Please bring your diary with you to this visit.


Please allow 1-2 weeks for the final report to be sent to your doctor to review. Your doctor will share the results with you.

Who to Call

UW Health Digestive Health Center
750 University Row
Madison, WI
(608) 890-5000
(855) 342-9900

East Madison Hospital
4602 Eastpark Blvd.
Madison, Wisconsin 53718
(608) 242-2898
(608) 440-6300

University Hospital
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.