So, I've had continuous bad acid reflux this week (new symptom) and was advised to try a self-test for low stomach acid in which you drink 1/4 tsp of bicarb in 8 fl. oz of water first thing on an empty stomach, and time how long it takes you to burp. Within 2-3 minutes is normal. It's been 27 minutes now and nothing has happened. I took 4 Gaviscon tablets last night - they're the kind that form a raft on top of your stomach contents to stop acid being sprayed into the gullet. Would that have invalidated the test?