24-hour pH Probe Study

What is a pH Probe?

A pH PROBE is a 24-hour test that measures the frequency of stomach acid that backs up into the esophagus. It is done as an outpatient procedure and requires no sedation. You or your child will have a small flexible tube passed through one nostril and positioned in the esophagus.

Slight gagging may be experienced momentarily as the tube is passed. Placement is verified with a chest X-ray. The tubing is then attached to a recorder and you or your child may resume normal daily activities. You will be asked to keep a diary of your food intake, heartburn and position (sitting, lying down) during this time.

After the completion of the 24 hours you will be asked to return to have the tube removed. Results will be sent to the physician that ordered the exam.

What is impedance?

Impedance measures electrical resistance across two electrodes. When reflux occurs the electrical resistance is decreased. The electrical resistance is also reduced when swallowing occurs. The impedance monitors attached to the pH probe can tell the difference between the two.

This technology is added to the pH probe and so both acid and nonacid reflux can be measured. Impedance can also differentiate reflux from swallowing.

The technology of pH measurement and impedance provides much more information for your doctor than a pH probe alone.