Test for acid reflux more convenient than previous tests.
D004947:Esophagus / Q000737:chemistry; D005745:Gastric Acidity Determination / Q000295:instrumentation*; D005764:Gastroesophageal Reflux / Q000175:diagnosis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018670:Monitoring, Ambulatory / Q000379:methods