N21.0 — Calculus in bladder
N21.0 is a billable, specific ICD-10-CM code for calculus in bladder. It is valid for submission on a claim.
Excludes2 — not included here, but may coexist
The excluded condition is not part of this code, but a patient can have both. You may code both.
- staghorn calculus (N20.0)
Inclusion terms
Alternative wordings a physician may use in the chart for this same code.
- Calculus in diverticulum of bladder
- Urinary bladder stone
Risk adjustment
N21.0 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
How N21.0 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to N21.0.
- Cystolithiasis
- Calculus, calculi, calculous›bladder(encysted) (impacted) (urinary) (diverticulum)
- Calculus, calculi, calculous›cystic
- Calculus, calculi, calculous›vesical(impacted)
- Cystitis›calculous
- Stone›bladder(diverticulum)
- Calculus, calculi, calculous›diverticulum›bladder
- Stone›urinary›bladder(diverticulum)
Related codes at this level
Codes that share N21. If N21.0 is not quite right, the correct code is usually one of these.
Questions about N21.0
- Is N21.0 a billable ICD-10-CM code?
- Yes. N21.0 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does N21.0 sit in the tabular list?
- Diseases of the genitourinary system (N00-N99), in the block Urolithiasis (N20-N23).