Actually you have been able and ARE still able to bill a PC for each and every lab test, CBC, LDH, tumor marker, Cross Match, Blood culture etc including send out tests......
the difficulty is that not many payors recognize these charges. Medicare doesnt pay them at all and instead reimburses these on a per hour basis allocated to pathologists as monthly directorship fees.
Blue Cross was successfully sued in Tenn I believe to have to recognize these charges, my prediction is that this will be the norm in the next 5 years or so.
The issue is that many pathology groups out of ignorance or laziness, marginalize CP and simply dont bill for crap...they are idiots IMO and hasten further degredation of the speciality. Personally I bill for it, spend alot of time doing CP related activities and am quite happy with the returns.
The ethical issue you have is that Medicare is essentially paying for services you are giving away for free to for profit insurance...technically this is illegal. No one has been called on it, but my prediction is that those groups who dont bill for CP pro fees will lose their Medicare Part B monies in the future.
As for starting your own CP lab, LOTS of people try it, none really succeed. It is far too big of a money maker for private medical centers (on the order of 10+ million in profit for a medium sized hospital) to give up now.