ICDcodes.org
FY2027

N11.1 vs N20.9

N11.1 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 N11.1
calculous pyelonephritis (N20.9)
N11.1

Chronic obstructive pyelonephritis

Billable
Chapter 14
Diseases of the genitourinary system
Section
N10-N16
Use when the record says
  • Pyelonephritis (chronic) associated with anomaly of pelviureteric junction
  • Pyelonephritis (chronic) associated with anomaly of pyeloureteric junction
  • Pyelonephritis (chronic) associated with crossing of vessel
  • Pyelonephritis (chronic) associated with kinking of ureter
  • Pyelonephritis (chronic) associated with obstruction of ureter
  • Pyelonephritis (chronic) associated with stricture of pelviureteric junction
  • Pyelonephritis (chronic) associated with stricture of ureter
Indexed under
  • Pyelonephrosis (obstructive)
  • Obstruction, obstructed, obstructive › pyelonephritis
  • Pyelonephritis › chronic › associated with ureteral obstruction or stricture
  • Pyelonephritis › chronic › obstructive
  • Pyelonephritis › in › obstruction
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