I have written extensively on my Collin County DWI blog about the current law enforcement trend toward mandatory blood testing on citizens accused of drunk driving. Many of our clients ask questions about the legality of forcing citizens to give a blood sample. Although the current state of Texas Law allows law enforcement to obtain a blood warrant to forcible extract a sample of your blood, I along with man other defense attorneys and legal scholars share the belief that this police is against established Texas law and United States Constitutional law.