@amyjph and
@sls314 hit the nail on the head. I realized I had typed up my response prior, but never posted it, so here it is - giving basically the same advice above.
Basically, you may never bill the services of one provider under another provider, unless there is a specific guidance to do so (like incident-to or Locum Tenens or reciprocal billing.) It may be true that other practices are doing this. It is also true that those practices are doing something very, very wrong. I don't like to use the "F" word (fraud), but fraud is intentionally submitting a claim you know is incorrect for the purposes of getting payment. It is always a struggle when having a new doctor join to keep them busy during that lag from start date to insurance credentialed date. Other than intentionally submitting incorrect claims, here are some suggestions to keep this provider at least somewhat productive.
1) All patients with the 3 insurances she is credentialed with or self pay get funneled to her.
2) If any of your carriers will make a retro-active participation date, she may see those patients as well. Some will. Some won't. Those claims should be held until that retroactive par date is updated.
3) Provide services that would not be billable anyway. Prescription renewal calls. Test results. Postop global care. Peer-to-peer authorization reviews. My group does hospital rounds both AM and PM. The non-credentialed provider could do one of those rounds, and the visit would be billed under the other provider who also saw the patient that day.
4) You could offer patients the option of seeing the new out of network provider if they want to be seen sooner than waiting for the fully booked other provider. If that is being done, you would need to provide patients with good faith estimates and make them aware this is out of network.
5) Make a business decision for the new provider to see patients and not charge for it.
Also, use this as a learning experience to start credentialing a new provider BEFORE they start. I recommend as soon as contracts are signed.