I'd imagine that if they check, they check in every instance. As in, if they are good scientists/lab technicians they should be following a routine process. That said, I don't live in a place where people are routinely required to provide urine samples.
Used it 5 times in the past for jobs and passed every single time. My buddy screwed it up by not microwaving it before he left for his test. So as long as the temp is good, then you are good. Best thing to do is over heat it a little, then if it's too hot dunk it in the toilet water to cool it off a bit. My grow journal http://forum.grasscity.com/indoor-grow-journals/1323166-another-noob-his-first-grow.html
Typically, labs don't randomly test samples for uric acid (which is the main issue with synthetic urine). Unless, you live in California, Ohio, West Virginia, Oregon, or Washington, then uric acid is often part of the standard testing for all samples in labs. So, the big question is the state you live in. But, there is synthetic urine available with uric acid to add or premixed. Some forms of QuickFix (6.0 and 5.7 I believe) and Serious Monkey Business being a few of them.