Receiving denials from Medicare because coders are using the negative result of the allergy testing (Z78.9) as the primary dx which does not meet med necessity per LCD policy. Is this following correct coding guidelines for this service? For other scenarios, like surgeries, I know we report the post op dx or we wait for a path report before selecting the dx code. In this case, those guidelines don’t make sense to me if the pt has other confirmed diagnoses. The pt’s dx is not "No reaction to allergy testing" when she has confirmed and documented asthma, allergic rhinitis and other diagnoses -all meeting medical necessity- and all indications for ordering the prick test to begin with.

Any feedback or publications you can refer me to regarding this would be greatly appreciated.