A 24-hour esophageal pH study measures how much stomach acid backs up into the food pipe in 24 hours. The most common uses for this gold standard test are:

• To diagnose gastroesophageal reflux disease (GERD, a feeling of heartburn, pain and food coming back up)
• For patients with other problems (such as atypical chest pain, recurring pneumonia or throat symptoms)
• Pre- and post-treatment evaluation to determine if medication dosage is correct
• For pre- and postsurgical heartburn
• For non-cardiac chest pain

• Do not eat or drink anything after midnight (If you are diabetic, please talk to your primary care doctor)
• 72 hours before the test, stop taking all antacids (Zantac, Prevacid, Prilosec, etc.), unless told otherwise by your doctor. You may take your other scheduled medications two hours before the test with small sips of water.