Burnt Toast is correct. The at home testing drug & pregnancy kits are not very different from the ones used in the actual lab testing facilities. These test kits do not identify positive or negative based on a color reaction as they are Antigen Specific. To clarify- an Antigen in this case would be any foreign substance [THC] not normally found in the body or (not normally found in high concentration [HCG] for pregnancy tests).

Masking is impossible but diluting is possible however the urine temp is (SUPPOSED TO BE) checked and logged at the time of collection. The urine should most likely be close to body temp. Any liquid used for diluting should be kept under your arm pit to reproduce a similar temp.