Is N21.9 a billable ICD-10-CM code?

Yes. N21.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does N21.9 sit in the tabular list?

Diseases of the genitourinary system (N00-N99), in the block Urolithiasis (N20-N23).

What cannot be coded together with N21.9?

N21.9 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

N21.9

N21.9 — Calculus of lower urinary tract, unspecified

Billable / specific codeICD-10-CM

N21.9 is a billable, specific ICD-10-CM code for calculus of lower urinary tract, unspecified. It is valid for submission on a claim.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

calculus of urinary tract NOS (N20.9)

Risk adjustment

N21.9 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 N21.9 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 N21.9.

Calculus, calculi, calculous›urinary›lower
Stone›urinary›lower tract

Related codes at this level

Codes that share N21. If N21.9 is not quite right, the correct code is usually one of these.

Questions about N21.9

Is N21.9 a billable ICD-10-CM code?: Yes. N21.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does N21.9 sit in the tabular list?: Diseases of the genitourinary system (N00-N99), in the block Urolithiasis (N20-N23).
What cannot be coded together with N21.9?: N21.9 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.