Can gerd cause a breathalyzer test to register high if there was no belching observed during the testing period?

No. : The breathilizer is positive because the blood alcohol is measured high in expired air from the lungs.

Breathalyzer: The breathalyzer has a built in mechanism called a slope detector. It is designed to recognize a slow or gradual increase in alcohol content as you exhale or blow out the air you have just taken in after a deep breath. If you have acid reflux or regurgitate while you have alcohol in your stomach, this causes a sudden rise in the alcohol content in your breath. The slope detector rejects that value.