Wireless pH study (Bravo capsule)

This leaflet has been written by staff working in the Endoscopy Unit at Chelsea and Westminster Hospital.

We hope you find it useful. If, after you have read it, you have any questions or concerns; please contact us on 020 3315 3056/5223.

When you come into the Unit (2nd Floor, Lift Bank B), please talk to us about any worries and ask any questions you have.

If you would like to change your appointment time or date, please contact the Endoscopy Unit booking team on 0203 315 4141/5984 or email us Chelwest.cwdiagnosticcentre.admin@nhs.net.

Your appointment time in Endoscopy is approximate because some procedures may take longer than expected and emergency procedures need to take priority. Please expect to be in the department for a couple of hours - having pre-procedure checks, the procedure and for recovery after the procedure.

What is a wireless pH study (bravo capsule)?

This test is used to examine the amount of acid passing up from the stomach into the gullet. The capsule is a small pill that attaches to the lining of the gullet above the valve above the stomach. The capsule sends wireless signals to a receiver to record the acid levels in the gullet over 48 hours.

We will discuss the possible complications with you before you sign the consent form.

What should I do before I come in for my test?

If you are having sedation, you must organise for someone to take you home after the test and be with you for the next 24 hours.


Unless advised otherwise, if you are taking any of the following medicines please stop taking them accordingly:

1 week before the test: Omeprazole (Losec), Lansoprazole (Zoton), Esomeprazole (Nexium), Pantoprazole (Protium), Rabeprazole (Pariet).

48 hours before the test: Ranitidine (Zantac), Cimetidine (Tagamet), Famotidine (Pepcid), Gaviscon, Rennies.

These tablets are reducing acid created by your stomach and if you stop taking the medication it will help us to get a clearer diagnosis.

If you are taking any of the following medicines, please inform the pre-assessment nurse or a member of the Endoscopy team for further instructions: 

  • Warfarin, rivaroxaban, apixaban, dabigatran, edoxaban
  • Clopidogrel, prasugrel, ticagrelor
  • Aspirin
  • Any other medication used to thin the blood (anti-coagulant)

Do I need to fast before the test? 

Your stomach must be empty for us to perform the gastroscopy. Therefore it is essential you have nothing to eat for at least six hours before the examination (see your letter). You may drink small sips of clear fluids (water, black tea or black coffee) and your usual medication until 2 hours before your appointment.

What are the risks and benefits?

The benefit is that the procedure will help us to investigate your symptoms and it may help us to treat you. Potential, though rare, complications specific to the pH study investigation include:

• Aspiration of the capsule (where the capsule may accidentally enter the respiratory system).

• The device failing to attach to the oesophagus or sending a signal, resulting in a failure to record.

• Failure of the capsule to detach from the oesophagus within the expected time or abnormal discomfort or pain caused by the capsule, either of which may in very rare circumstances require endoscopic removal.

We will discuss the possible complications with you before you sign the consent form.

What will happen when I come in?

On admission to the unit a nurse will ask you several questions about your health, current medication (please bring an up-to-date list with you), and take your blood pressure and pulse.

You do not need to bring anyone with you to your appointment, unless they are acting on your behalf (eg interpreting for you). Your escort/relative will only be needed when you are discharged if you have sedation. Please avoid bringing cash or valuables with you.

Prior to the test you will be seen by the endoscopist doing the test for you. This is an opportunity to discuss the test before you sign a consent form. Please ask any questions you may have. It is important that you understand what is going to happen.

What can I expect during my test?

The procedure will be as described in the Gastroscopy leaflet supplied separately.

When the examination is finished, the gastroscope will be removed quickly and painlessly. The camera will then be removed and the capsule will be inserted through the mouth and down the throat to the required position.

The capsule is pinned to the lining of the gullet and it will then transmit signals to a receiver. The receiver is about the size of a mobile phone and can either be carried in an over shoulder pouch or clipped onto your belt. The capsule will send signals to the receiver for 96 hours, when the receiver will stop recording automatically. The capsule will stay attached to the lining of the gullet for between 5–12 days where it will drop off and passes naturally through your digestive system.

What happens to my medications?

We will talk to you before you go home about any changes/additions to your medications.

What can I expect after my test?

After the procedure you will be taken back to your cubicle. If you have had sedation, you will need to rest quietly until the sedative has worn off (usually an hour or so). The nurse will check your blood pressure and pulse.

There is a small chance that the capsule may fail to attach or may detach early (before the end of the 96-hour recording period). If this were to happen the test may, with your consent, need to be repeated on a different day.

You should avoid having an MRI scan for 30 days following placement of the capsule. There is metal in the capsule, and the capsule therefore needs time to pass through your digestive system before it is safe to have an MRI scan.

If an MRI scan is required before the end of this 30 day period it is important that you mention that you have had this test, to the doctor requesting the MRI scan as they may need to perform an X-ray first.

There is a small risk of developing an allergic reaction/ anaphylaxis to the metal contained within the capsule. If you have previously experienced a metal allergy please let us know and you will be advised whether it is safe to proceed with the test prior to the gastroscopy.

If you have any problems or concerns, please contact the Endoscopy Unit from 8am–6pm on 020 3315 3056/5223.

Outside of these times please call St. Mary Abbot ward on 020 3315 8602 / 8603 or go to your nearest A&E remember to take your endoscopy report with you.


Q: Will I get the results of my test on the same day?
A: After you return the recorder, we would analyse the data. The results will be communicated to you at your next clinic appointment.
Q: Will the test be uncomfortable?
A: It is perfectly normal to feel some mild chest pain during the investigation, or to feel the capsule tugging in the oesophagus when you are eating. Any discomfort should be relieved with over the counter pain relief. In very rare cases some patients experience more significant discomfort. It is advised that you seek medical attention if you are concerned about the levels of discomfort you are feeling.
Q: What options are available for the procedure?
A: You will be given either sedation, or an anaesthetic throat spray for the examination. We will have already have discussed with you which one you would prefer. We recommend sedation for a pH Study. The sedation will not put you to sleep but will make you feel drowsy and relaxed. The anaesthetic spray will only numb your throat.

If you decided to have sedation, then a small needle will be inserted into your arm or hand and you will be given an injection through this.

1. Endoscopy Governance Team 2. Dr Kinesh Patel (Consultant Gastroenterologist) 3. Dr Ibrahim Al Bakir (Consultant Gastroenterologist) 4. Dr Daniel Galloway (Consultant Gastroenterologist) 5. Dr Neerav Joshi (Endoscopy Clinical lead / Consultant Gastroenterologist) 6. Helen Morgan (Pharmacist) Camelia King-Martey