Hypothetical situation: I understand this is open to interpretation and that there are variables.

In a "justifiable" shooting in Va. Where you appear to have fired in self defense, do the Police check your blood alchohol level? Do they check to see if you are high or have been smoking dope?
My son just asked and I do not know the answer.
Thanks

While I'm no expert in this subject I would suspect that the only reason you would get this check is if you gave reason for the officers to suspect that drugs/alchohol were involved.  If you are not showing any signs of being intoxicated or stoned I don't think any type of blood or urine test would be done.  

If there's any sort of indication that you were affected or impaired by anything, then it will be checked.  A few years back I worked a shooting that I felt (and still do) was justified where the guy told me that he had smoked a joint earlier in the day and had drank a beer a few hours earlier.  I did a search warrant for a blood test and ultimately found that the levels were not a factor (IIRC his BAC was 0.015 and the MJ barely registered), but any sort of substance in your system will not be helpful in the long run, particularly in terms of how you are perceived.

Thank you gentelmen.