Originally Posted by Tandem Rider
I don't understand why the ambulatory pH test is not used more for diagnosis.
For GERD, it is definitely the most accurate test. However, barium swallow or endoscopy can be used to diagnose other conditions, as well, including more immediately dangerous ones such as cancer. It's also fairly expensive and pretty inconvenient for the patient. Finally, very few clinics and not all hospitals perform the test.
So, they generally scope first, to check for dangerous stuff, then treat you presumptively for GERD, or (if the symptoms don't sound that bad) start drug therapy first. Ambulatory pH studies are usually performed only with people who have very bothersome symptoms that aren't responding well to drugs, OR in people considering surgery for reflux, who need to be very sure of the diagnosis.