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ICD-10 Guide
ICD-10 CodesChapter 14: Diseases of the genitourinary systemN21

N21

Billable

Calculus of lower urinary tract

Chapter 14:Diseases of the genitourinary system

BILLABLE STATUSYes
IMPLEMENTATION DATEOctober 1, 2015
LAST UPDATED09/18/2025

Code Description

ICD-10 N21 is a billable code used to indicate a diagnosis of calculus of lower urinary tract.

Key Diagnostic Point:

Calculus of the lower urinary tract refers to the presence of stones (calculi) in the bladder or urethra. These stones can form from various substances, including calcium, oxalate, uric acid, and struvite, often as a result of dehydration, dietary factors, or metabolic disorders. Symptoms may include hematuria (blood in urine), dysuria (painful urination), and urinary obstruction, which can lead to significant discomfort and complications if left untreated. Diagnosis typically involves imaging studies such as ultrasound or CT scans, and treatment options may include lithotripsy, which uses shock waves to break up stones, or surgical removal in more severe cases. Dietary modifications, such as increasing fluid intake and reducing oxalate-rich foods, can help prevent recurrence. Understanding the underlying causes and appropriate management strategies is crucial for effective treatment and patient education.

Code Complexity Analysis

Complexity Rating: Medium

Medium Complexity

Complexity Factors

  • Variety of potential underlying causes for stone formation
  • Need for precise documentation of symptoms and imaging results
  • Differentiation between types of urinary calculi
  • Potential for co-existing conditions affecting treatment

Audit Risk Factors

  • Inadequate documentation of stone type and location
  • Failure to document dietary modifications or patient education
  • Misclassification of the type of urinary calculus
  • Lack of imaging results in the medical record

Specialty Focus

Medical Specialties

Urology

Documentation Requirements

Detailed imaging reports, patient history, and treatment plans.

Common Clinical Scenarios

Patients presenting with flank pain, hematuria, or urinary obstruction.

Billing Considerations

Ensure accurate coding of the type of calculus and any associated procedures performed.

Nutrition

Documentation Requirements

Dietary assessments and recommendations for stone prevention.

Common Clinical Scenarios

Patients with recurrent urinary stones requiring dietary intervention.

Billing Considerations

Document specific dietary changes and patient adherence to recommendations.

Coding Guidelines

Inclusion Criteria

Use N21 When
  • Follow official ICD
  • 10 coding guidelines, ensuring accurate documentation of the type of calculus and any associated symptoms
  • Include relevant imaging studies and treatment plans in the medical record

Exclusion Criteria

Do NOT use N21 When
No specific exclusions found.

Related CPT Codes

50590CPT Code

Lithotripsy, extracorporeal shock wave

Clinical Scenario

Used for patients with calculi in the lower urinary tract requiring non-invasive treatment.

Documentation Requirements

Document the size and location of the calculus, as well as the patient's response to treatment.

Specialty Considerations

Urologists should ensure that all imaging studies are available for review.

ICD-10 Impact

Diagnostic & Documentation Impact

Enhanced Specificity

ICD-10 Improvements

The transition to ICD-10 has allowed for more specific coding of urinary calculi, improving the accuracy of data collection and reimbursement processes. It has also facilitated better tracking of treatment outcomes and patient demographics.

ICD-9 vs ICD-10

The transition to ICD-10 has allowed for more specific coding of urinary calculi, improving the accuracy of data collection and reimbursement processes. It has also facilitated better tracking of treatment outcomes and patient demographics.

Reimbursement & Billing Impact

reimbursement processes. It has also facilitated better tracking of treatment outcomes and patient demographics.

Resources

Clinical References

  • •
    American Urological Association Guidelines

Coding & Billing References

  • •
    American Urological Association Guidelines

Frequently Asked Questions

What are the common causes of lower urinary tract calculi?

Common causes include dehydration, dietary factors (high oxalate or sodium intake), metabolic disorders, and urinary tract infections.