W33 vs Y09
W33 (Accidental rifle, shotgun and larger firearm discharge and malfunction) compared with Y09 (Assault by unspecified means), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. W33 carries an Excludes1 note covering Y09: “assault (X92-Y09)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| W33Accidental rifle, shotgun and larger firearm discharge and malfunction | Y09Assault by unspecified means | |
|---|---|---|
| Billing status | Non-billable header Report instead: W33.00XA, W33.00XD, W33.00XS, W33.01XA, W33.01XD | Billable |
| Classification | V00-Y99 — External Causes of Morbidity (V00-Y99) | V00-Y99 — External Causes of Morbidity (V00-Y99) |
| Definition | Accidental rifle, shotgun and larger firearm discharge and malfunction is a non-billable ICD-10-CM category code (W33). | Assault by unspecified means is a billable ICD-10-CM diagnosis code (Y09). |
| 7th character | The appropriate 7th character is to be added to each code from category W33 | — |
| Includes | rifle, shotgun and larger firearm discharge and malfunction NOS | homicide injuries inflicted by another person with intent to injure or kill, by any means Assassination (attempted) NOS Homicide (attempted) NOS |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources