Deige already answered that question. If youre consistently testing negative on the home test using the first urination of the day, youre good to go.

Anytime you test yourself with a home test, you always use the first urination of the day when THCA concentrations would be at their highest. By doing this, you are testing yourself under the "worst-case scenario".
Taking a home test during the later portions of the day skews the results due to fluids you may have consumed (as part of normal routine) during the course of the day. The fluid consumption dilutes the THCA concentration that is present in the bladder to where a urine sample registers a negative (providing that the THCA concentration in the bladder is not too high). This phenomena is only temporary - once youve urinated out all the fluids youve consumed, the bladder is replenished with fresh THCA-laden urine and thus the donor would resume testing positive for THC.