This has been an ongoing issue for quite some time now. In my experience the greatest chances of success are coding the ICI related diarrhea as ulcerative colitis ( K51.00-51.8- these codes encompass variations on UC + complications), clinical documentation has to reflect the accompanying diagnosis code.
The greatest issue that we encounter are the delays in approval, that a PA may take several days, so if we suspect that a diarrhea situation may be headed toward needing infliximab, we start the auth process in the out pt setting. Sometimes the coding can be an issue and complicate the process if a coder submits the wrong code, based on their interpretation of the clinical information.
If a patient is referred to our ER for immunotherapy induced diarrhea that is refractory to steroids, we have been successful in patients receiving infliximab in the ER.
In patient, we have not experienced the third party payer issues in quite some time, as the patients are correctly diagnosed and coded upon being admitted for ulcerative colitis.