A. It certainly does need to be used. The modifiers that are set forth by the Federal Medicare for use with anesthesia services are extremely important and must always be utilized. When preparing anesthesia charges for submission to Medicare or any other payer, there are several modifier choices to consider, AA, QK, QY, QX, QZ, QS. These modifiers indicate important aspects of the anesthesia administration such as what specialty is the provider -physician anesthesiologist or a Certified Registered Nurse Anesthetist, whether or not the CRNA is being Medically Directed by an anesthesiologist, and / or whether or not the case involves the anesthetic administration technique referred to as Monitor Anesthesia Care or MAC. Whomever is handling the coding and billing should be completely aware and intimately familiar with these modifiers and the proper use of them.