Not sure? Check your referral or call the clinic — it will say one of these.
24-hour pH / impedance study
A thin, flexible catheter is passed through your nose into your oesophagus. It measures acid levels for 24 hours while you go about your day. No sedation is needed.
Fasting
Fast for at least 4–6 hours before your appointment (no food or drink). Small sips of water for essential medications are usually OK — confirm with the clinic.
Medications to stop
Only stop medications if your doctor or the clinic has told you to. Some studies are done “on” your reflux medication, others “off” — it depends on what your doctor needs to measure.
Medication type
When to stop (if instructed)
Examples
PPIs (proton pump inhibitors)
7 days before
Nexium, Somac, Pariet, Losec, Zoton
H2 blockers
48 hours before
Famotidine (Pepcid), ranitidine
Antacids (over-the-counter)
24 hours before
Gaviscon, Mylanta, QuickEze, Rennie
Prokinetics
48 hours before
Motilium (domperidone), metoclopramide
Continue all other regular medications unless told otherwise.
What to expect
At the clinic (~30 min) — a thin catheter is passed through one nostril and taped in place. It’s uncomfortable for a moment but not painful. No sedation — you can drive.
The next 24 hours — you go home with a small recorder clipped to your belt. Eat normally, sleep normally, go to work. You’ll keep a simple diary of meals, symptoms, and when you lie down.
No bath or shower while the catheter is in (the recorder can’t get wet).
Return next day — the catheter is removed (takes seconds) and the data is downloaded.
Bravo wireless pH capsule
A tiny capsule is clipped to the lining of your oesophagus during an endoscopy. It wirelessly records acid levels for 48–96 hours — no catheter on your face. It falls off on its own within about 2 weeks.
Fasting
Fast from midnight the night before (same as an endoscopy). No food, drink, or chewing gum.
Medications
Same withholding rules as the catheter pH study (PPIs 7 days, H2 blockers 48 hours, antacids 24 hours) — only if your doctor has told you to stop. The clinic will confirm when you book.
What to expect
Endoscopy (~15 min, sedation) — the capsule is placed during a short endoscopy. You’ll need sedation, so arrange someone to drive you home.
48–96 hours recording — you carry a small receiver (about the size of a pager). No catheter on your face, and you can shower normally.
Keep a diary of meals, symptoms, and position changes — same as the catheter study.
No MRI while the capsule is inside you (usually detaches within 5–14 days). Confirm with your doctor before scheduling any MRI.
Return the recorder — as instructed by the clinic. The capsule passes naturally and doesn’t need to be retrieved.
Nuclear medicine reflux scan (scintigraphy)
You swallow a drink containing a small amount of radioactive tracer, then a gamma camera takes images to see whether stomach contents reflux into the oesophagus, throat, or lungs. It’s non-invasive — no tube, no sedation.
Fasting
Fast from midnight the night before (or at least 4 hours). No food, drink, smoking, or chewing gum.
Medications
Stop gastrointestinal medications 48 hours before if your doctor or the nuclear medicine department instructs you to. Otherwise, continue your regular medications.
What to expect
Drink the tracer — a small cup of liquid (usually water or orange juice) mixed with a tiny amount of radioactive tracer. It has no noticeable taste.
Imaging (~60–90 min) — you’ll lie on a scanning table (and sometimes sit upright) while the camera takes images. It doesn’t hurt.
After the scan — no restrictions. You can eat, drink, and resume normal activities immediately. The tracer passes out of your body naturally within hours.
Radiation exposure is very low — comparable to a few months of natural background radiation. It’s considered safe, but tell the department if you are pregnant or breastfeeding.
Good to know (all reflux tests)
What to bring
Your referral letter, Medicare card, a list of your current medications (including over-the-counter), and comfortable clothing without metal buttons or zippers (for nuclear scans). For Bravo — bring a driver.
Why is my doctor ordering this?
Reflux studies help your doctor see how often stomach contents flow back into the oesophagus, how acidic they are, and whether reflux may be reaching the throat or lungs. They’re usually ordered when symptoms haven’t responded to treatment, before reflux surgery, or to investigate an unexplained cough, voice changes, or throat symptoms.
Will it hurt?
The pH catheter is uncomfortable to swallow (a brief gagging sensation) but most people adjust within minutes. The Bravo capsule is placed under sedation, so you won’t feel it. The nuclear scan involves no discomfort at all — you just lie still.