If you are arrested for suspicion of DUI/DWI, you are obligated to undergo a chemical test of your breath, blood, or urine at a police station or local hospital. If you refuse, you will incur stiff penalties, including suspension of your driver's license and a longer sentence if convicted. Chemical tests are generally reliable but not infallible. For example, police station breathalyzers may be thrown off by alcohol-containing substances in the mouth, such as breath fresheners and mouthwashes. Low-carb diets produce acetone on the breath, which may be identified as alcohol. Even a burp before blowing into the machine may cause a false-high reading. Urine test are the least reliable of the three chemical tests. It takes longer for alcohol to be metabolized by the body and appear in a person's urine, generally 60-90 minutes. Because of this, a person may be required to give two urine samples - first sample given; bladder voided; wait 20 minutes; give a second sample. This pur...