The 24 hour pH doesn't reveal problems of the esophagus. It does measure any incidents of reflux that you might be having during the 24 hr period that you have the probe in. It will measure the frequency and duration of any refluxing incidents. The attached computer records the incidents as they happen. The doctor will compare the incidents to an activity log that you keep. They will then compile a "score" based upon your results.

Both times that I had a 24 hour pH probe test, I also had a Manometry. The Manometry is a probe that measures the contractions of your esophagus. It also helps them locate where your lower esophageal sphincter. It measures the pressure of your les. This helps them determine the correct placement of the pH probe and also identifies if your LES is closing properly.

If you are having reflux coming up, there is a possibility of esophageal damage. Typically an upper endoscopy is performed in order for the doctor to visually see if there is damage.

I've had all three tests done twice over the last 3 years. The Manometry shows that I have good esophageal motility, but my LES doesn't close properly. The 24 hr pH probe shows severe incidents of reflux. The EGD showed that even with all the years of refluxing, I didn't have any damage to my esophagus.