I am not an expert in this area, but I will attempt to answer your question based on our situation here at Hartford Hospital which is similar to the one you describe in your e-mail.  Our PC (professional corporation) bills for Part B (professional) services on all consultations from other institutions and the Hospital bills for the Part A (technical) services.  Yes, codes for histochemical stains (88312 & 88313) and immunoperoxidase stains (88342) are billed along with 88321 (consult - slides only) or 88323 (consult - slides & blocks).  We use 88325 for extremely complex consultations requiring review of medical records, x-rays, etc.  along with the examination of slides and/or blocks.  If the consult originates from an inpatient at the referring institution your Hospital must (in most cases) bill the referring institution, not the patient's insurance.  This is because the Hospital receives payments from Medicare/HMOs/other 3rd party payor that cover all Part A services on their patients.  Our PC also does "Facility-billing" when requested.  I would also appreciate hearing from others on this topic (especially if I have said anything wrong).

RWC