N21.0

✓ Billable

Calculus in bladder

Diseases of the genitourinary system (N00-N99)

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Also Known As

Calculus in diverticulum of bladderUrinary bladder stone

⚠️ Excludes2

direct

Both codes can exist if both conditions are documented.

• staghorn calculus (N20.0)

Clinical Description

ICD-10-CM code N21.0 represents calculus in bladder. This code falls under the Diseases of the genitourinary system (N00-N99) classification. It is a billable/specific code valid for HIPAA-covered transactions as of October 1, 2025 (FY2026). This code can be used to indicate a diagnosis for reimbursement purposes on insurance claims.

This is a 5-character code at the 4th level of specificity. This is the most specific code available in this subcategory.

Frequently Asked Questions

What is ICD-10 code N21.0?

ICD-10-CM code N21.0 is "Calculus in bladder". It belongs to the category: Diseases of the genitourinary system (N00-N99).

Is N21.0 a billable ICD-10 code?

Yes, N21.0 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.

Can N21.0 be coded with other codes?

N21.0 has 1 Excludes2 note(s). These conditions can be coded together if both are documented in the patient record.

Related Codes in N21

Other codes in the same category that may be relevant for differential coding:

N21.1Calculus in urethra N21.8Other lower urinary tract calculus N21.9Calculus of lower urinary tract, unspecified

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Code Information

CodeN21.0

BillableYes

ParentN21

CategoryDiseases of the genitourinary system (N00-N99)

Excludes10 rule(s)

Excludes21 note(s)

Data Source

CMS ICD-10-CM 2026 Tabular List

Updated October 1, 2025 (FY2026)