Do the police take blood samples to their own lab for a DUI case?

I was involved in a car accident on 1/13/2014. I blacked out at the wheel and hit a utility pole in PA. I was brought to the ER. I am a Type 1 diabetic and was extremely dehydrated and my blood sugar was very high which the ER doctor told my father could definitely caused the black out. I had a bottle of RX pain meds in the car. The bottle was open due to the fact that I took 2 pills in the pharmacy parking lot. In the ER the State Trooper said there were 17 pills missing from the bottle He said I would hear within 2 weeks about the toxicology report. He called me 3 months later and said there 96 mgs of percoset in my blood (which I have never heard of a test that measure mgs) and he was charging me with DUI. I requested my blood work from the hospital, which showed I had blood work for a CBC but not a drug screen. I did have a urine test for drug screening which was negative for opiates. Do the police take blood samples to their own lab? Do the police have to ask for consent to take a blood test for a drug screen because I was never asked? I am very confused.