Question: Our practice is expanding, and we will soon have two new physicians starting who are not yet credentialed with any of our insurance companies. Can we let these physicians see patients and then bill for those services? Louisiana Subscriber Answer: The answer depends on the carrier. Here's what you need to know to ensure you properly integrate these physicians into your billing system. Medicare: Medicare will allow you to hold your physicians- claims from the date they apply for their Medicare provider numbers and then file them once the physicians receive their credentialing from Medicare. You can do this for all of your physicians- Medicare services while they remain without credentials. Medicare will pay your claims retroactively from the date of the new physician's 855 application. Private payers: Check with the individual payer. Some non-Medicare payers may give you an effective date for when you can start billing. Most payers will not take claims from dates of service prior to the date when they approved the physician as a credentialed paneled participating physician with their plan. Remember: You cannot bill services under another provider while you-re waiting for the new physicians- credentialing completion. There is no such thing as a physician billed "incident to" another physician. Try this: When a patient needs to see a physician before that physician is credentialed, you can take the private-pay/non-participating route, if the patient is willing. Be sure to allow your office plenty of time when trying to credential a new physician. The process can take 90 days or even longer, according to Medicare. Experts recommend that you initiate this process as far in advance of a new physician's starting date as you can. If you can act early, you-ll have the necessary credentials in place when the physician starts seeing patients, and you won't have to hassle with delayed payments. -- The answers to the Reader Questions were reviewed by Barbara J. Cobuzzi, MBA, CPC-OTO, CPC-H, CPC-P, CPC-I, CHCC, president of CRN Healthcare Solutions in Tinton Falls, N.J.