An officer who asks you to provide a chemical test (primary test) is also required by law to be prepared to perform a secondary test.  The police department is on the hook to pay for the secondary test.  However, unless you request the secondary test, the cops do not have to provide one to you.  If you request a secondary test, and if they don’t provide it to you, there might be an argument to get the primary test thrown out.  Whether this will happen will depend on the specific facts in the case.  Thus, if you request a secondary test, and the cops don’t give you one, you should contact an attorney immediately. 

If you want someone of your own choosing to take a chemical test of your blood, breath or urine, the law requires the officer to allow you to do that.  However, you must make the arrangements for that test.  Once again, if the officer impedes your ability to get your own test done, then there might be an argument to get the primary test thrown out.  Whether this occurs will depend on the specific facts of the case.  Thus, if an officer denies your request for your own test, you should immediately contact an attorney.

Note: You must take all tests requested by the officer before you can request a secondary test or obtain a test by someone of your own choosing.