Here is the Fact I've read from the package of AZO, "This product can interfere with labarotory tests including urine, glucose, and ketones." Now I'm not sure how it interferes, but the fact is this is written inside the package.
What they actually mean is that it may interfere with tests for medical conditions such as glucose, ketones etc.
It in no way, shape, or form refers to tests for THC, or any other drugs of abuse. Such tests use an entirely different reagent that what is used for tests for medical conditions.