Y1 Denial Code (Deactivated) – Use P21

Y1 is a retired claim adjustment reason code. Payers stopped using it on 07/01/2014. Current remittances use P21 instead.

Seeing Y1 on a Remittance?

Y1 was retired effective 07/01/2014 and should not appear on new remittances.
Payers now report this situation with P21 — check that page for current guidance.
Official retirement note: Use code P21
If Y1 appears on an old ERA you are reworking, interpret it per the remittance date, then follow the current code's guidance for any corrected claim.