I’d just like to second what Michelle has just said really and Sean.  You sound very knowledgeable Tom and the best kind of advocate for your son to have.  

I was unsure about how your son was diagnosed and just hoping that it had been picked up on testing at birth as opposed to diagnosis for hospital admittance.  I guess the only thing you can do from here is ensure that you get to see the Doctor Carol recommended earlier.    That and the tests you feel you need to get done to satisfy your curiosity and find out more. 

As for testings of electrolytes, I don’t think it is possible to get a good result from blood spots in those.  Unlike blood sugar and 17 OHP etc.  I have never heard of anything like that anyway.  It would be nice to do those on any test with just blood spots as opposed to a full blood draw, but apparently Ashley prefers blood draws to blood spot testing.  :)  He hates having his fingers pricked.  Having seen five babies get heel pricks, it does not look any less painful having those done either.  :)