24-Hour pH Testing

24-hour pH testing is a diagnostic procedure that continuously monitors acid reflux activity in your oesophagus (food pipe) over a complete day-night cycle. This test uses a thin, flexible catheter equipped with sensitive pH sensors that detect and record changes in acidity levels, capturing both acidic and non-acidic reflux episodes throughout your daily activities, including eating, sleeping, and physical movement.

The extended monitoring period allows your doctor to identify silent reflux episodes, correlate your symptoms with actual reflux events, and measure total acid exposure time. This comprehensive data is invaluable for diagnosing gastroesophageal reflux disease (GERD), evaluating treatment effectiveness, and determining whether your chest pain, chronic cough, or other symptoms are truly related to acid reflux, helping your gastroenterologist develop the most appropriate personalised treatment plan.

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What to Expect

During the 24-hour pH test, you'll wear a monitoring device while continuing your normal daily routine. Here's what the process involves:

• A thin tube is placed through your nose into your oesophagus.
• The tube is connected to a small recorder you wear on your belt or shoulder.
• You go home and carry on with your usual activities for 24 hours.
• You will keep a diary of your meals, sleep, and symptoms.
• You return the next day to have the tube removed.

Pre-Procedure Instructions

To ensure accurate test results, please follow these important preparation instructions before your appointment:

• Fasting: Do not eat or drink for 6 hours before your test.
• Medications:
  Stop the following unless your doctor instructs otherwise:
  
  • Proton Pump Inhibitors (omeprazole, esomeprazole, pantoprazole, lansoprazole, rabeprazole): stop 7 days before
  • H2 Blockers (ranitidine, famotidine, nizatidine): stop 48 hours before
  • Antacids (Gaviscon, Maalox, Tums): stop 24 hours before
• Clothing: Wear loose, comfortable clothes to fit the recorder.

Your doctor will inform you about additional preparations required.

Post-Procedure Instructions

After the procedure and during the monitoring period, follow these simple care instructions:

• Once the tube is removed, you can eat, drink, and take your medicines as normal.
• Mild sore throat or nasal discomfort may occur for a few hours.
• Avoid heavy exercise or swimming while the tube is in place.
• Seek medical help if: you develop persistent nosebleed, chest pain, difficulty breathing, or fever.

Frequently Asked Questions

What does a 24-hour pH test show?

A 24-hour pH test measures how often stomach acid enters your oesophagus, how long it stays there, and whether your symptoms correlate with actual reflux episodes. The test detects both acidic and non-acidic reflux events, identifies silent reflux without symptoms, and determines total acid exposure time, helping your doctor diagnose GERD and assess whether symptoms like chest pain or chronic cough are caused by acid reflux.

What are the side effects of a 24-hour pH test?

The test is generally well-tolerated with minimal side effects including mild sore throat, nasal congestion, or slight discomfort whilst the tube is in place, which typically resolve within hours after removal. Serious complications are extremely rare, and most people can continue normal daily activities throughout the monitoring period.

Will the procedure be painful?

The test is not painful, though you may feel some mild discomfort during the 24-hour monitoring period. The procedure does not require sedation or anaesthetic.

Am I allowed to eat normally during monitoring?

Yes, maintaining your regular eating and drinking habits is encouraged as this ensures the test accurately reflects your typical daily conditions.

Can I shower during the test?

Showering and bathing should be avoided throughout the monitoring period to prevent the recording device from getting wet.

Estimated Costs

Indicated charges are estimates of the full price, and subsidies will depend on the individual. The information presented is accurate as of September 2025.

• Singaporeans (Private rates): $1294.90 (before GST)
• Permanent residents and non-residents (Private rates): $1653.16 (before GST)

If you have questions, please contact your doctor or the Gastrointestinal Function Unit (GIFU) before your test.