Which statement about 24-hour pH monitoring is true?

• A. It measures acid exposure over 24 hours and may be combined with impedance monitoring.
• B. It directly visualizes mucosal breaks.
• C. It measures esophageal pressure during swallowing.
• D. It is used to treat GERD.

Answer: (A)

The main idea is that 24-hour pH monitoring records how much acid enters the esophagus over a full day and can be paired with impedance monitoring to detect reflux events regardless of acidity. This combination lets you quantify acid exposure and also capture nonacid reflux by watching impedance changes as refluxed material moves. It’s a diagnostic test that helps determine whether GERD is contributing to symptoms and guides management. It does not directly visualize mucosal breaks (that’s endoscopy), it does not measure esophageal pressure during swallowing (that’s manometry), and it is not a treatment.