Ive been motiering my piss with walmart piss tests for the past 2 weeks. I hope there accurate compared to the probation lab tests. But no one seems to know. These walmart tests claim to test for dilution, but I know there not as complex and thurough as lab tests. Ive tested my self from dirty to clean within 20 days. The walmart tests are a little different from the home tests Ive read about. Ive read that getting a line means being positive. ON these tests there oppisite. If you have a line that means your negative, and if you dont have one it means your positive. I got a faint line for thc.