What to Expect During a 96-Hour Bravo pH Test for GERD?

A 96-hour Bravo wireless pH test is a procedure that measures how often and how long acidic fluid enters your esophagus (your swallowing tube). Instead of having a catheter taped to your nose for days, your doctor temporarily attaches a tiny capsule to the lining of your esophagus. Over four days, this capsule wirelessly transmits acid measurements to a small receiver. While it cannot measure the total volume of reflux or detect non-acid reflux, it provides objective data to help diagnose gastroesophageal reflux disease (GERD).

How the Capsule is Placed

The Bravo capsule is typically placed during an upper endoscopy—a routine procedure where a flexible camera is guided down your throat ^[1].

Sedation is commonly used to keep you comfortable, though the exact type varies by center ^[2]. You may receive moderate sedation (leaving you drowsy and relaxed but not fully unconscious) or deeper anesthesia ^[2]. Using a small vacuum suction, the doctor draws a tiny bit of your esophageal tissue into the device to pin the capsule securely against the wall of your esophagus ^[3]. When you wake up, the capsule is already recording and sending data to a small wireless receiver that you carry with you.

Because you receive sedation, you will need a ride home and must follow your facility’s restrictions, such as not driving for the rest of the day.

Important Safety Warning: Avoid MRI Scans

Because the Bravo capsule contains metal and electronic components, it is not safe for MRI (Magnetic Resonance Imaging) machines ^[4]. You must avoid MRI scans for a specific period after placement (often 30 days), or until a doctor confirms with an X-ray that the capsule has fully left your body. Always notify any imaging provider or emergency staff that you have a Bravo capsule in your esophagus.

Will I Feel It in My Throat?

Because there is no wire through your nose, the wireless test interferes much less with your daily life than catheter-based tests ^[5]. However, it is not completely invisible to your senses. The capsule is fixed to the wall of your esophagus, not hanging in your throat, so it generally does not block swallowing.

• Expected Discomfort: It is common to be mildly aware of the capsule when you swallow food, or to feel a vague tightness in your chest. In some clinical studies, roughly half of patients reported mild to moderate chest discomfort during the test ^[6]. A sore throat or mild bloating from the endoscopy is also normal.
• When to Call the Clinic: A small retrospective study documented severe post-procedure pain in roughly 8 to 9% of patients ^[7]. If you experience persistent difficulty swallowing, you should contact your testing center ^[8].
• Medical Emergencies: Severe or new chest pressure/pain, shortness of breath, fainting, sweating, pain spreading to the arm or jaw, or vomiting blood are medical emergencies. Do not wait for a clinic callback; call 911 or go to the nearest emergency room, as these could be signs of a serious heart or esophageal issue ^[4].

Medications: What to Stop and When

Your doctor will give you explicit instructions regarding your acid-blocking medications, such as Proton Pump Inhibitors (PPIs), H2 blockers, or antacids. Never stop a prescribed medication without explicit instructions from your clinical team.

• Testing Off Medication: If the goal is to see if you truly have GERD, you will likely be told to stop taking your PPIs for a specific period (often around 7 days) before the test ^[9][10]. H2 blockers and antacids often have different, shorter stop intervals. This allows your doctor to see your natural acid levels. Be aware that your reflux symptoms may temporarily worsen during this time.
• Testing On Medication: If you already have proven GERD but continue to have symptoms despite treatment, your doctor might occasionally test you while you stay on your PPIs. However, this is more commonly done using a different test called impedance-pH monitoring, which uses a catheter to detect both acid and non-acid reflux ^[9][11].

Your Role: The Receiver and Symptom Diary

The 96-hour test requires your active participation. You must keep the receiver within range (typically within a few feet) and keep it dry. Throughout the four days, you will use the buttons on the receiver and keep a written diary to log:

• When you eat and drink
• When you lie down, as acid exposure often changes when you are resting flat ^[12]
• When you feel symptoms, such as heartburn, regurgitation, or chest pain.

The software uses a statistical calculation called the symptom association probability (SAP) ^[13]. This looks at whether your reported symptoms happened within a specific time window after an acid reflux event ^[14]. It does not definitively prove cause and effect, but it helps your doctor understand patterns. If you forget to press a button, it does not invalidate the test or erase the total acid data—it just makes the correlation between symptoms and acid slightly less reliable.

Detachment and Passing the Capsule

The Bravo capsule is designed to separate spontaneously from your esophageal wall, usually within a few days to a week, and pass harmlessly in your stool ^[8]. You will likely never see it or feel it pass.

At the end of the testing period, you will return the receiver and diary to the clinic. Your doctor will then review the data. If the capsule does not detach as expected, or if your doctor needs to verify it has left your body (especially if you need an MRI), they may order a simple X-ray ^[8]. Very rarely, a retained capsule might need to be removed during another endoscopy ^[15][3]. Always ask your doctor when you should restart your reflux medications after the test is complete.