another website says that some testing parameters are ph tests (which based on the below description would seem to address the issue of uric acid, though I thought from review of the quick fix synthetic urine that proper ph was present in quick fix):

see e.g.
section on Urine Specimen Validity (Adulteration)Test

at
Urine Sample Adulteration Test


pH tests for the presence of acidic or alkaline adulterants in urine. Normal pH levels should be in the range of 4.0 to 9.0. Values outside of this range may indicate the sample has been altered.