AAPC has a really great Webinar which gives some insight into when to use modifier -24. The webinar is called "Coding with Modifiers: CPT, Medicare and the Real World" and was put on by Timothy Canterbury, CPC, CPC-I. He explains that the CPT definition of the surgical package includes "Typical" post-op follow up. Since returning to the hospital as an IP 3-weeks post-op is not typical, this would suggest that this service is not included in the surgical package definition and should be reimbursable. Mr. Canterbury cites CPT Assistant which says that E/M services for complications that require significant additional work are appropriate to be separately reported with modifier -24. However, CMS has their own interpretation of the surgical package and say that they have taken into consideration that there will be times where time additional services will be required due to complications and they have computed this into the CMS reimbursement of the surgical package. So, depending on your payer, there are times when you can, quite appropriately bill for E/M services for complications from from/of a surgical procedure using modifier -24. CMS specifically states, though, that if the E/M is due to a complication it is related to the initial procedure and modifier -24 is inappropriate.
The webinar also discusses the appropriate uses of modifiers -58, -78 and -79, among others. I highly recommend it.
However, I will say that I agree that if the provider feels that the services in this admission are included in the surgical package, regardless of the payer, then the service should not be billed from an ethical viewpoint.
Karen Hill, CPC, CPB, CPMA, CPC-I