Incident-to different 5th digit

How much does the 5th digit on a diagnosis code matter when meeting incident-to requirements for an established diagnosis?

For example: A patient has been previously diagnosed and plan of care established for a COPD diagnosis. Now the patient comes back to the office, sees the NP, the visit meets all the requirements for incident-to except the diagnosis now is COPD with exacerbation and the 5th digit on the code is different the the original one the physician billed when the patient was not in exacerbation.

Would this still qualify for incident-to?

incident to, different 5th digit on diagnosis code

The CMS manual isn't this specific. The care must be for a problem that the physician has seen first, and initiated the plan of care. If it's an exacerbation of the same problem, I probably would bill it as incident to. A new problem of course not. I am not aware of any carriers who are this specific about how to judge: new or exacerbation.

It's really judgment.

exacerbation

Use 491.21 for acute exacerbation
Use 496 for unspecified COPD unless the patient also has one of the following:
Asthma with COPD 493.2x
Bronchitis with COPD 491.2x
COPD with acute bronchitis 491.22
Emphysema with COPD 492. 8
Code 496 is inclusive to and not assigned for any condition classified to 491-493
Example: code 491.21, "obstructive chronic bronchitis with acute exacerbation."
This code specifically identifies the patient as having some elements of chronic bronchitis, COPD and emphysema, and indicates that these clinical problems are not controlled.

Incident-to different 5th digit

Thank you both for your info, this is very helpful.