Is it possible I may never be charged with a DWI (OVI) ?

Question:  4 months ago I got into a minor accident (in terms of vehicle damage) after I hit a snow bank. The police came to the scene and I was next to incoherent, although it was not clear to the officers that I was necessarily intoxicated (although I assuredly was, between alcohol and prescribed codeine). I was taken to the hospital and they got a warrant for my blood. I have received absolutely no word about the incident from the court, and I do not have a warrant as I have checked weekly since the incident. Today marked the completion of my substance abuse program, which I did both for myself and to help my legal case should it come to that (which I have fully expected it to). I have no idea when or if this whole thing is going to come down on me. Any advice on what to expect now? 

Answer:  It is possible, albeit unlikely, you won't be charged. They may have lost the sample, never sent it in, mishandled it, etc. More likely your sample is still at the laboratory, and they have not gotten around to testing it yet. I am surprised they did not just file the charges, because typically Police file an "impaired" charge and just wait for the results. If you fail, they can then file a "per se" charge in addition to the impaired.