24-hour pH study is a way to measure frequency of acid reflux episodes. It is useful in evaluating patients with acid reflux, heartburn, chest pains, chronic cough, voice hoarseness, and other throat symptoms. A thin, flexible catheter is introduced through the nose into the throat or esophagus in the office. The rest of the test is conducted in patient's home environment over the next 24 hours. pH (level of acidity) is recorded either in the throat or esophagus.

The test helps to determine how often acidic stomach content is reaching the voice box or esophagus. The test is painless and is well tolerated. It does not require any special preparation.

‍