N21: Calculus of lower urinary tract
Codes under N21 (Calculus of lower urinary tract). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| N21.0 | Calculus in bladder | ✓ |
| N21.0 | Calculus in bladder | ✓ |
| N21.1 | Calculus in urethra | ✓ |
| N21.1 | Calculus in urethra | ✓ |
| N21.8 | Other lower urinary tract calculus | ✓ |
| N21.8 | Other lower urinary tract calculus | ✓ |
| N21.9 | Calculus of lower urinary tract, unspecified | ✓ |
| N21.9 | Calculus of lower urinary tract, unspecified | ✓ |
Frequently asked questions
What is ICD-10-CM code N21?
N21 is an ICD-10-CM category covering Calculus of lower urinary tract. It contains 8 more specific diagnosis codes, 8 of which are billable.
Is N21 a billable code?
No — N21 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example N21.0 — Calculus in bladder). 8 of the 8 codes under N21 are billable.
What codes fall under N21?
N21 includes N21.0, N21.0, N21.1, N21.1, N21.8, plus 3 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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