Reference laboratories as a rule of thummb perform all the tesing i.e ABO/Rh and AB screen. I previously oworked at a facility where the labs had different CLIA license number, but same umbrella institution. Since, we did not want to double bill our patients, we repeated Type and screens, but did not charge the patients. there was a addendum out witht he results that the testing was performed at our lab and there was no associated charge. The only charges wer for Antibody ID, screen units nad performing XM's. The general laboratory had charges build in for specimen transfer and such.