The QF had always had creatinine ("buffers") in it - right from its introduction over a decade ago. During that period, Ive used many batches with success and tested dozens more (using the Urinecheck adulteration test strip). Ive had a few batches that failed my strip tests (which were all subsequently exchanged) but those batches were either expired or exposed in direct sunlight.
When a batch is expired, the creatinine "buffers" break down to zero, resulting in a 'non-human' ruling at the labs. When a batch has been exposed to direct sunlight, all of the constituent "buffers" break down, resulting in a "non-human" ruling.

When I purchased the QF the associate at my local head shop informed me that Sonoran Labs are now testing for Creatine which is naturally produced by the human body. He said if you're not going to Sonoran Labs you have nothing to worrry about.
The headshop associate doesnt know what s/he is talking about and needs to stick with just selling tokeware. All labs certified by DHHS (including Quest, Labcorp, Kroll, Concentra, etc) perform validity tests to make sure the urine samples creatinine, specific gravity, pH, and nitrites are within acceptable limits.
Burnt Toast Reviewed by Burnt Toast on . Quick Fix 5.7 Results First of all, thank you to all of the posters that have encouraged the use of Quick Fix. I hand an upcoming urinalysis and was apprehensive about the process since it had been 10 years since the last one I have taken. I scoured this forum for months in preparation for the test. I too was a bit unsure if Quick Fix would really work, but in the end (after much deliberation) I decided that it would indeed be my best option. I followed the directions and passed. The sample was given at a local Rating: 5