Digestive Disease: Tests of the Esophagus: pH Test

The 24-hour esophageal pH test is an outpatient procedure performed to measure the pH or amount of acid that flows into the esophagus from the stomach during a 24-hour period.

The procedure is commonly used to help identify the cause of various symptoms, including:

• Heartburn, primarily in patients who have failed medical treatment and are candidates for surgery
• Uncommon symptoms of GERD: (gastroesophageal reflux disease) such as chest pain, chronic cough and asthma.

How Is the Test Performed?

The equipment used in the esophageal pH test consists of a small probe that is inserted through your nostril and positioned near the lower esophagus. The probe is plugged into a small unit (or monitor) worn on your belt or over your shoulder.

The device has several buttons that, when pressed, record:

• The occurrence of symptoms.
• The times when you eat and lie down.

A nurse will review the monitoring instructions with you.

Be careful with the monitor and keep it dry at all times.

How Should I Prepare for the Test?

Do not eat or drink for 4 to 6 hours before your doctor's appointment.

Tell your doctor if you are pregnant, have a lung or heart condition or any other diseases, or are allergic to any medications.

Can I Continue to Take Medication Before the Procedure?

There are several medications that may affect the results of an esophageal pH test. These include:

• Proton pump inhibitors: Prilosec, Prevacid, Nexium, Aciphex, Protonix
• H2 blockers: Axid, Pepcid, Tagamet, Zantac
• Antacids: Alka-Seltzer, Gaviscon, Maalox, Milk of Magnesia, Mylanta, Tums
• Calcium channel blockers: Calan, Adalat, Isoptin, Cardizem, Dilitiazem, Procardia
• Nitrates: Isordil, Isosorbide, Nitrobid, Nitrodisc, Nitroglycerin (NTG), Nitropatch

There are other medications that may affect the test results. Talk to your doctor about all medications you are taking before undergoing the procedure.

Do not discontinue any medication without first consulting with your primary or referring doctor. If proton pump inhibitors need to be discontinued, you will take a week off these medications before doing the test.

What Should I Do During the Monitoring Period?

Throughout the monitoring period, there are several things you need to be aware of to assure accurate results:

• Activity: Try to follow your usual routine during the monitoring period. Many people tend to reduce or change their activities during the testing period; however, such changes can affect reflux occurrence and make the results of the monitoring period less useful. Do not take a bath or shower during the monitoring period, as the equipment cannot get wet.
• Eating: Eat your regular meals at the usual times and eat the way you normally do. 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. You need to eat at least two meals a day. Eat foods that tend to increase your symptoms (without making yourself miserable!). You may drink as much plain water as you want.
• 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 normal daily routine.
• Medications: Continue following your doctor's recommendations regarding which medications to avoid during the monitoring period.