If you are arrested for drunk driving the police may ask you to submit to a blood or breath test. If you refuse to submit to their request, then you may be cited for Refusal, in addition to any OWI and BAC/PAC citations that you may receive. If you do refuse, then you have 10 days from the date you were given notice in which to demand a refusal hearing.
If you submit to the officer's primary test request, often times a blood test, you have the right to request secondary test, i.e., an alternative test. If you are not given the opportunity for the alternative test that you have requested, the court may then suppress the results of the first test at trial. And, it's hard for the state to get a conviction without the test result.