pH Impedance Testing

A pH sensor detects acid. That is useful, and for many people it is enough. But not everything that refluxes is acidic, especially in someone already taking acid suppression, and a pH sensor is blind to material that is not acidic.

Impedance measures electrical resistance between closely spaced sensors. Liquid, gas, and air each change that resistance differently, so the study can see material moving up the esophagus regardless of its acidity, and can tell how far up it travels.

Combining the two gives a complete picture: what refluxed, whether it was acidic, how high it reached, and whether you felt anything when it happened.

The most common reason is persistent symptoms on a proton pump inhibitor. If acid is already suppressed and you still feel it, the question is no longer how much acid there is. It is whether reflux is still happening in another form, or whether reflux was never the cause.

The second reason is a symptom pattern that is not burning. Regurgitation, chronic cough, throat clearing, hoarseness, and the sensation of a lump can all come from nonacid material reaching high in the esophagus.

The third is planning. Before any procedure aimed at reflux, an objective record of what is refluxing and whether it correlates with symptoms is worth having.

You arrive fasting. A numbing gel is used and a thin flexible catheter is passed through one nostril and positioned in the esophagus, then secured so it stays put. The recording box clips to your clothing or a strap.

You go home and live a normal day. Eat your usual meals, sleep in your usual position, and press the marker button whenever a symptom occurs. Meals and lying down get logged too.

You return the next day, the catheter is removed in seconds, and you are finished. Some people have a mildly sore throat afterward and nothing else.

This is the decision that shapes the whole study. Testing off acid suppression asks whether you have reflux at all. Testing on it asks whether your ongoing symptoms are still coming from reflux despite treatment.

Both are legitimate questions and only one can be answered per study. You will be told which applies to you and how far in advance to hold or continue medication.

The analysis produces total reflux episodes, how many were acidic, how many were not, how high material traveled, and the correlation between events and the symptoms you logged.

A strong correlation supports treating reflux more aggressively. A poor correlation with a normal acid burden is just as valuable, because it points the search elsewhere and spares you a procedure that would not have helped.

This page is educational information, not medical advice. What is right for you is decided in consultation, after a review of your history, your symptoms, and your testing.