context: The 24-hour esophageal p H test is an outpatient procedure performed to measure the p H or amount of acid that flows into the esophagus from the stomach during a 24-hour period. The p H test 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 The equipment used in the esophageal p H 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 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. When preparing for the esophageal p H 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. There are several medications that may affect the results of an esophageal p H test. These include: Proton pump inhibitors: Prilosec (omeprazole), Prevacid (lansoprazole), Nexium (esomeprazole), Aciphex (rabeprazole), Protonix (pantoprazole), Dexilant (dexlansoprazole), Zegerid (omeprazole/ sodium bicarbonate) H2 blockers: nizatidine, Pepcid (famotidine), Tagamet (cimetedine), Zantac (ranitidine) Antacids: Alka- Seltzer, Gaviscon, Maalox, Milk of Magnesia, Mylanta, Tums Calcium channel blockers: Calan (verapamil), Adalat, Procardia (nifedipine), Cardizem (dilitiazem) 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 may need to take a week off these medications before doing the test. Throughout the monitoring period of the esophageal p H test, 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 should not 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 some 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. During the monitoring period of the p H test, make sure you keep accurate records: Record your primary symptoms, as discussed with your doctor, by pressing the appropriate buttons on the monitor when the symptoms occur. Record the times when you are eating, drinking anything except water, or lying down (you do not have to be sleeping or intending to sleep when lying down). Record the following: The time when you start eating The time when you finish eating The time when you start lying down The time when you finish lying down You may resume your normal diet and activities after the esophageal p H test. If your throat feels sore following the test, suck on lozenges. At your next appointment, your doctor will discuss your test results. A device known as BRAVO may make monitoring the p H level easier. Instead of having to have a tube placed down your nose for 24 hours, your doctor will place a disposable capsule into the esophagus using an endoscope. The capsule then wirelessly transmits information about esophageal acid activity to a receiver worn around the waist for 48 hours.