N12 vs N20.9
N12 and N20.9 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on N12
calculous pyelonephritis (N20.9)
N12
Tubulo-interstitial nephritis, not specified as acute or chronic
Billable
- Chapter 14
- Diseases of the genitourinary system
- Section
- N10-N16
Use when the record says
- Interstitial nephritis NOS
- Pyelitis NOS
- Pyelonephritis NOS
Indexed under
- Pyonephritis
- Nephritis, nephritic › antitubular basement membraneNEC (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic)
- Nephritis, nephritic › tubulo-interstitial (albuminuric) (azotemic) (congenital) (disseminated) (epithelial) (familial) (focal) (granulomatous) (hemorrhagic) (infantile) (nonsuppurative, excretory) (uremic)
- Pyelonephritis › nonobstructive
- Disease, diseased › antiglomerular basement membraneantibody › tubulo-interstitial nephritis
N20.9
Urinary calculus, unspecified
BillableUnspecified
- Chapter 14
- Diseases of the genitourinary system
- Section
- N20-N23
Indexed under
- Anuria › calculous
- Calculus, calculi, calculous › anuria
- Calculus, calculi, calculous › urinary
- Stone › urinary (s)
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