Breathalyzer

A police officer pulls over this guy who had been weaving in and out of the lanes.
He goes up to the guy's window and says :
- Sir, I need you to blow into this breathalyzer tube.
The man says :
- Sorry officer I can't do that. I am an asthmatic. If I blow in this breathalyzer I'll have a really bad asthma attack.
- Okay, fine. I need you to come down to the station to give a blood sample.
- I can't do that either. I am a hemophiliac. If I do that, I'll bleed to death.
- Well, then we need a urine sample.
- I'm sorry officer I can't do that either. I am also a diabetic. If I do that I'll get really low blood sugar.
- Alright then I need you to come out here and walk this white line.
- I can't do that, officer.
- Why not ?
- Because I'm too drunk to do that !