nope never an issue with quick fix my GF just used it about a year ago and I had a good friend of mine use it about 4 months ago to get a real nice job. I just switched to test clear because it actually smells like piss and foams up. Just buy extra heat packets to practice getting the bottle to the right temp witch is not hard to do. I have carried the bottle in my boot, underwear and hell one time I carried it in my back pocket! I have done extensive research on this subject and I concluded that in some states and countries have different testing standards and test for "uric acid" I believe and the regular quick fix sold at head shops does not have it. However the "Canadian" quick fix you can buy from there website comes with a small vial of uric acid to add to the bottle just prior to droping the sample. I have not heard of any cases from people I know in Michigan using QF "as long as the bottle is the right temp and there are no clerical errors". In all of my internet searches I came up with only a few claims of QF failing and none of test clear failing so that what I went with.