What is the ICD-10 (International Classification of Diseases, 10th Revision) code for a patient referred from a Primary Care Physician (PCP) to urology for ureterolithiasis (kidney stone in the ureter)?

ICD-10 Code for Ureterolithiasis Referral

The appropriate ICD-10 code for referral from a primary care physician to urology for ureterolithiasis is N20.1 (Calculus of ureter). 1

Diagnostic Classification of Ureterolithiasis

• Urinary stones are classified according to their anatomic position, with ureteral stones specifically coded as N20.1 in the ICD-10 classification system 1
• The European Association of Urology guidelines specifically classify stones according to their location in the urinary tract, with stones in the ureter being distinctly categorized from those in other locations (renal pelvis, calyces, or bladder) 1
• Ureterolithiasis refers specifically to stones located in the ureter, which can be further subclassified by their position within the ureter (proximal, middle, or distal) 1

Diagnostic Evaluation Supporting the Code

• Standard evaluation for suspected ureterolithiasis includes detailed medical history, physical examination, and appropriate imaging studies 1
• Non-contrast CT is the gold standard imaging modality for confirming the diagnosis of ureterolithiasis prior to referral, with 93.1% sensitivity and 96.6% specificity 1
• Ultrasound may be used as an initial diagnostic tool (45% sensitivity, 94% specificity for ureteral stones), but should be followed by CT if ureterolithiasis is strongly suspected 1
• Basic laboratory evaluation should include urinalysis, serum creatinine, uric acid, and ionized calcium to assess for underlying metabolic conditions 1

Coding Specificity Considerations

• The N20.1 code specifically refers to calculus of ureter, distinguishing it from:
  • N20.0 (Calculus of kidney)
  • N20.2 (Calculus of kidney with calculus of ureter)
  • N21.0 (Calculus in bladder) 1
• Using the correct anatomical location in the code is essential for proper documentation and appropriate treatment planning 2
• The ICD-10 system provides greater specificity than previous coding systems, allowing for more precise documentation of the stone's location 2

Clinical Management Implications of Coding

• Accurate coding as N20.1 helps determine appropriate treatment algorithms based on stone location 1
• Treatment options for ureteral stones vary based on location within the ureter (proximal, middle, or distal), with different success rates for each modality 1
• Pain management for patients with ureteral stones typically involves NSAIDs as first-line therapy, with opioids as second-line options when needed 3
• Medical expulsive therapy with alpha-blockers may be considered for facilitating passage of ureteral stones, particularly for distal ureteral stones >5mm 3

Common Pitfalls in Coding Ureterolithiasis

• Avoid using general codes like N20.9 (Urinary calculus, unspecified) when the specific location is known 2
• Do not confuse with N20.0 (Calculus of kidney) when the stone has migrated to the ureter 1
• When both kidney and ureteral stones are present simultaneously, use N20.2 (Calculus of kidney with calculus of ureter) instead of N20.1 1, 2
• If hydronephrosis is present due to the ureteral stone, this should be coded separately with the appropriate hydronephrosis code (N13.1) in addition to N20.1 4