The simple answer is that you are allowed to refuse a breath or blood sample. However, if you refuse, an officer can then apply for a warrant to get a sample of your blood. If the officer obtains a warrant, he or she can take a sample of your blood without your consent- and use reasonable force to do so if necessary.
In Texas, when we get a driver’s license, we are giving our “implied consent” that we will provide a specimen of our breath or blood if we are pulled over. However, we are able to revoke our consent. Revoking your consent would then mandate an officer get a warrant to take your blood.