Wiki primary diagnosis selection for hospital outpatient facilities vs ASCs

[cmclaughlin]

Hi everyone — I’m looking for peer input to confirm best practice regarding primary diagnosis selection for hospital outpatient facilities vs ASCs.

In hospital outpatient surgery, my understanding is that we follow ICD-10-CM Section IV for facility billing, which instructs us to:

• Use the symptom as the RFV (reason for visit),
  but
• If a definitive condition is established during the procedure (ex: stricture, mass, polyp), the confirmed finding becomes the primary diagnosis for the facility claim.

However, ASC billing seems to differ in practice, as many ASC coder resources and payer guidance indicate that the symptom often remains the primary diagnosis, and the definitive finding is listed second — even when discovered during the procedure.

For those who code/audit in both settings:

• Do you apply this distinction consistently (hospital Outpatient = finding as PDX vs ASC = symptom as PDX)?
• And is this driven more by CMS guidance, payer policy, or industry convention?

I would appreciate insight or examples of how others handle this across the two facility types.

Thanks

 

[TThivierge]

Hi everyone — I’m looking for peer input to confirm best practice regarding primary diagnosis selection for hospital outpatient facilities vs ASCs.

In hospital outpatient surgery, my understanding is that we follow ICD-10-CM Section IV for facility billing, which instructs us to:

• Use the symptom as the RFV (reason for visit),
  but
• If a definitive condition is established during the procedure (ex: stricture, mass, polyp), the confirmed finding becomes the primary diagnosis for the facility claim.

However, ASC billing seems to differ in practice, as many ASC coder resources and payer guidance indicate that the symptom often remains the primary diagnosis, and the definitive finding is listed second — even when discovered during the procedure.

For those who code/audit in both settings:

• Do you apply this distinction consistently (hospital Outpatient = finding as PDX vs ASC = symptom as PDX)?
• And is this driven more by CMS guidance, payer policy, or industry convention?

I would appreciate insight or examples of how others handle this across the two facility types.

Thanks

CMClaughlin
You go by the expert provider s outpatient final primary diagnosis code(can be a symptom or definitive dx).They are the medical expert and should give you the final dx code listed in their documentation. The final listing assessment or impression of dx should have documented for the medical coder to assign the proper dx code to it. I do know if the R symptoms code used as primary when the definitive dx is listed you get less funding. Also take in the fact of unspecified dx can be given & used but if more detail or definitive dx is a better choice IF THE PROVIDER has given you that final documented dx code. Remember the types & levels of different dx in which always try to select the closest given by provider. As examples some disease which have levels & specifics are DM, HTN,CHKD, Fractures, Hemorrhoids, Polyps or Neoplasm in certain body areas, Migraines, Obesity, Asthma, Hernia, Skin Ulcers, Etc.
CMS regs usually are what the other payers follow ..definitve dx or main illness problem listed first. The ICD10 manual list certain ds. can be primary whereas others cannot...insurance payers follow those rules. The Excludes 1 rules are followed too in case of dx. redundancy. Ensure follow the Z dx codes of which can be first on claim too and other Z dx codes listed last on claim.
I hope helped you!

Lady T