Excludes1 pair
N20.9 vs N21.9
N20.9 and N21.9 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
The official note, declared on N21.9
calculus of urinary tract NOS (N20.9)
N20.9
Urinary calculus, unspecified
BillableUnspecified
- Chapter 14
- Diseases of the genitourinary system
- Section
- N20-N23
Indexed under
- Anuria › calculous (impacted) (recurrent)
- Calculus, calculi, calculous › anuria (impacted) (recurrent)
- Calculus, calculi, calculous › urinary (duct) (impacted) (passage) (tract)
- Stone › urinary (duct) (impacted) (passage)
N21.9
Calculus of lower urinary tract, unspecified
BillableUnspecified
- Chapter 14
- Diseases of the genitourinary system
- Section
- N20-N23
Indexed under
- Calculus, calculi, calculous › urinary › lower
- Stone › urinary › lower tract
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027