In Missouri there in no constitutional right under Missouri Implied Consent law to speak with an attorney, but there is a limited right to seek the advice of an attorney. If you request to speak with an attorney, the officer is required to give you 20 minutes within which to contact one. This applies either before or after you are given the Implied Consent Warning. If you are not given 20 minutes without abandoning your search, the breath or blood results are inadmissible.
The Western District recently handed down an opinion regarding this issue in Sless Shaleen Riley vs. Director of Revenue, WD73956. In Riley vs. DOR, Riley requested to speak with an attorney several times but did not reaffirm her request after the Implied Consent Warning was read to her. The officer did not permit her to consult with an attorney and had her blood tested for alcohol. The court found that the BAC results from the blood test would have been inadmissible but for the fact that her attorney did not object to the admission of the results on any basis. Once evidence is properly admitted it can be used for any purpose. The objection has to be made to keep evidence out.