GERD can be diagnosed by symptoms and the response to medication.
In some cases of GERD, inflammation of the gullet may be seen on endoscopy (a procedure when a flexible tube is placed via the mouth into the gullet and stomach).
Oesophagitis
GERD can also be diagnosed with the help of 24-hour pH monitoring - a tube is placed through the nose to the gullet and the acidity is measured.
When combined with Impedance testing (where a tube with multiple electrodes is inserted into the gullet), one can differentiate the contents of the reflux fluid, thus guiding the doctor in treatment.