24-Hour Esophageal pH Test

What is an esophageal pH test?
An esophageal pH test measures and records the pH in your esophagus to determine if you have gastroesophageal reflux disease (GERD). The test can also be done to determine the effectiveness of medications or surgical treatment for GERD.

What is esophageal reflux?
Esophageal reflux is a condition in which stomach acid refluxes or moves back into the esophagus (the "food pipe" leading from the mouth to the stomach).

What happens during esophageal reflux?
A specialized muscle, called the lower esophageal sphincter, is located where the esophagus meets the stomach (see figure). This sphincter opens to allow flood and liquid to pass into the stomach, then closes. When the sphincter does not close tightly, food particles, stomach acid and other digestive juices can splash back up into the esophagus. When this happens, the condition is called gastroesophageal reflux. When reflux occurs on a regular basis, it can cause permanent damage to the esophagus. The esophageal pH test measures how often stomach contents reflux into the lower esophagus and how much acid the reflux contains.

How does the esophageal pH test work?
A thin, small tube with an acid sensing device on the tip is gently passed through your nose, down the esophagus ("food tube"), and positioned about 2 inches above the lower esophageal sphincter. The tube is secured to the side of your face with clear tape. The end of the tube exiting from your nose is attached to a portable recorder that is worn on your belt or over your shoulder. The recorder has several buttons on it that you will press to mark certain events. A nurse will review the monitoring instructions with you.

• Seven days before the monitoring period, do not take proton pump inhibitors: Prilosec (omeprazole), Prevacid (lansoprazole), Aciphex (rabeprazole), Protonix (pantoprazole), Nexium (esomeprazole)
• Two days (48 hours) before the monitoring period, do not take the H2 blockers: Zantac (ranitidine), Tagamet (cimetidine), Pepcid (famotidine), Axid (nizatidine); or the promotility drug, Reglan (metoclopramide)
• Six hours before the monitoring period, do not take antacids (such as Alka-Seltzer, Gaviscon, Maalox, Milk of Magnesia, Mylanta, Phillips, Riopan, Tums or any other brands)
• Four to 6 hours before your appointment do not eat or drink

Please note: Occasionally, your doctor may want you to continue taking a certain medication during the monitoring period to determine if it is effective.

• Activity: Follow your usual daily routine. Do not reduce or change your activities during the monitoring period. Doing so can make the monitoring results less useful.
• Note: do not take a tub bath or shower; the equipment can’t get wet.
• Eating: Eat your regular meals at the usual times. If you do not eat during the monitoring period, your stomach will not produce acid as usual, and the test results will not be accurate. Eat at least 2 meals a day. Eat foods that tend to increase your symptoms (without making yourself miserable). Avoid snacking. Do not suck on hard candy or lozenges and do not chew gum during the monitoring period.
• Lying down: Remain upright throughout the day. Do not lie down until you go to bed (unless napping or lying down during the day is part of your daily routine).
• Medications: Continue to follow your doctor’s advice regarding medications to avoid during the monitoring period.
• Recording symptoms: Press the appropriate button on your recorder when symptoms occur (as discussed with the nurse).
• Recording events: Record the time you start and stop eating and drinking (anything other than plain water). Record the time you lie down (even if just resting) and when you get back up. The nurse will explain this.
• Unusual symptoms or side effects. If you think you may be experiencing any unusual symptoms or side effects, call your doctor.

You will return the next day to have the tube removed. The information on the recorder will be downloaded to a computer and the results will be analyzed.

After completion of the study
Resume your normal diet and medications. Lozenges or hard candy may help ease any sore throat caused by the tube. Your doctor will discuss the results of your test with you during your next scheduled appointment.