Question: I have some cases where a CRNA does the preoperative evaluation but does not assist during the case. Should I be using the QZ modifier on the CRNA charge, or the QX? And what modifier goes on the anesthesiologist's charge? Maine Subscriber Answer: If the CRNA is only seeing the patient(s) for pre-op H&P, this service is included with the anesthesia procedure. Here's why: The H&P or pre-op assessment is included with the anesthesia services so there won't be a separate charge for it if the CRNA does the H&P and the anesthesiologist does the actual anesthesia case because you can't split out these services anyway. The exception to this rule is if the case ends prior to the administration of anesthesia and only the E/M is billed, and then you could bill under the CRNA who did the exam. Bill for the person who is handling the anesthesia procedures by the following methodology. For claims with a single provider: If the anesthesiologist does all the work, append modifier AA (Anesthesia services performed personally by anesthesiologist) to the appropriate anesthesia code. If a CRNA does the anesthesia work without medical direction from the anesthesiologist, append modifier QZ (CRNA service: without medical direction by a physician) to the anesthesia code. For claims that involve both the anesthesiologist and CRNA: If the anesthesiologist is medically directing one CRNA, include modifier QY (Medical direction of one certified registered nurse anesthetist [CRNA] by an anesthesiologist) on the anesthesiologist's claim and modifier QX (CRNA service: with medical direction by a physician) on the CRNA's. If the anesthesiologist is medically directing from two to four CRNAs, append modifier QK (Medical direction of two, three, or four concurrent anesthesia procedures involving qualified individuals) to the anesthesiologist's claim and modifier QX to the CRNA's. Remember that the anesthesiologist cannot medically direct more than four CRNAs (or other qualified anesthesia providers). If the number passes four, the anesthesiologist's work shifts from medical direction to medical supervision. In that case you would append modifier AD (Medical supervision by a physician, more than four concurrent anesthesia procedures) to the anesthesiologist's claim but still include modifier QX for the CRNAs.