Blood evidence is often critical to DUI prosecutions as well as any criminal case involving circumstantial evidence. In Pennsylvania the prosecution must establish beyond a reasonable doubt that the person operating a motor vehicle while under the influence through blood or breath evidence. There is a lesser DUI charge based on observation evidence but these are normally very weak cases and difficult to prove. Prosecutors normally want to introduce blood evidence into a trial to not only reinforce their case but to meet their burden of proof for more serious DUI charges. There are many cases, however, where medical professionals (EMTs, doctors, or nurses) obtain blood after a person is brought to the hospital following a car accident. It is important to understand that that Pennsylvania Motor Vehicle Code directs hospitals and staff to take blood samples of when an individual is brought for treatment following a motor vehicle accident. While these blood samples are normally used for the purpose of treating a person’s injuries and determining adverse reactions to drugs they are also potentially admissible in a criminal case.
In Pennsylvania law enforcement needs a search warrant to obtain blood samples from a hospital to test them for alcohol or drugs. A search warrant requires probable cause. If a police officer were to obtain the blood samples without a warrant a Court would more than likely find them inadmissible because the police officer would have violated the person’s rights under the Pennsylvania Constitution and potentially the US Constitution. While previous cases in Pennsylvania do not necessarily require search warrants, the Supreme Court in Commonwealth v. Shaw specifically made it a requirement. While some members of the Pennsylvania Supreme Court have written dissenting opinions which call into question the need for a search warrant given Pennsylvania’s “Implied Consent Law”. The Shaw case currently makes the law necessary.