Question: I’m coding for a procedure that included an anesthesiologist and CRNA. Can you clarify for me how to bill with the QY modifier? Indiana Subscriber Answer: When an anesthesiologist and CRNA work together, you need to append the appropriate “performance” modifiers to indicate each provider’s role in the procedure. The QY modifier (Medical direction of one certified registered nurse anesthetist (CRNA) by an anesthesiologist) shows that the anesthesiologist medically directed the CRNA during the case; you should only append it to the anesthesiologist’s claim. The corresponding modifier for the CRNA’s service when medically directed is modifier QX (CRNA service: with medical direction by a physician). Several other modifiers are available to indicate medical direction or medical supervision, depending on the circumstances. They are: QK (Medical direction of two, three, or four concurrent anesthesia procedures involving qualified individuals).