Question: Can you help me understand how insurance companies process a 50/50 split when an MD and a CRNA both submit separate bills for services? if the industry standard allowable amount is 50 percent, do I have to write off the remaining 50 percent, or can I bill the patient that amount? Nevada Subscriber Answer: If you are participating or have a contract with the insurance company, you bill the full amount under each provider then the insurer pays 50 percent to each, totaling 100 percent of the allowed amount. You write off the rest; otherwise, you would be “double dipping.” Here’s why: If you, as the billing provider, adjusts for the reduction, the insurer will reduce again since there is no way to know if what you are billing is the true amount or not. It falls under the premise that the physician and the CRNA share responsibility for providing the services so each gets a portion of the payment. However, you should check with the insurer to verify its preference for billing in these situations. Some payers will accept a single claim with only the MD name and two lines – one for the MD’s service with modifier AA (Anesthesia services performed personally by anesthesiologist) and one for the CRNA’s service with the appropriate Q- modifier.