hanks for the reply. Yes, this was the first urination of the day, why do you ask?
Because if you were to take that home test during the afternoon or later, the negative results would be skewed due to fluid consumption and urination occuring during the course of the day. Fluid consumption dilutes the THCA concentration in the bladder to where the urine sample registers a negative on the home test (or any assay screen for that matter). This phenomena is only temporary though. Once the fluids consumed had all been urinated out, the donor will resume testing positive for THC.

By using the first urination of the day, you are testing under the "worst case scenario" - THCA concentrations are at their highest and have not been affected by any fluid consumption.

And youve tested negative under that "worst case scenario", so youre good to go for the scheduled U/A.