In either case, if you're stopped for a suspected DUI, it can't hurt to ask to talk to an attorney if you have any doubt about whether you'd pass one of these chemical tests.
In most states, if you refuse to give a blood or urine test (or a breath test), your driver's license will be suspended automatically for anywhere from 90 days to one year. And, you can still be tried for driving while impaired. Even if you're found "not guilty" after trial, the suspension usually remains in effect.
Whether you have the option to choose the test you take depends on the laws of the state where you were stopped. Refusing to take a blood-alcohol test can have serious consequences, including an automatic suspension of your license for 90 days to one year, in addition to being prosecuted for drunk driving.
All states impose penalties that include some or all of the following: