ICD-10 Coding for Patient Reporting Passed Kidney Stone
For a patient who reports they think they passed a kidney stone, use ICD-10 code N20.0 (calculus of kidney) if there is documented history of kidney stones, or Z87.442 (personal history of urinary calculi) if the stone passage is confirmed and the acute episode has resolved.
Primary Coding Options
Active Stone Disease
- N20.0 (Calculus of kidney) - Use this code when the patient has a known kidney stone or recent stone episode, even if they believe it has passed, until imaging confirms complete stone clearance 1
- N20.1 (Calculus of ureter) - Use if imaging or clinical evidence suggests the stone was ureteral rather than renal 2
- N20.9 (Urinary calculus, unspecified) - Use when stone location cannot be determined but stone disease is documented 2
Resolved Stone Disease
- Z87.442 (Personal history of urinary calculi) - Use this code only after confirmed passage and resolution of the acute episode, typically with follow-up imaging showing no residual stones 1, 3
Clinical Context for Code Selection
The choice between active disease codes (N20.x) versus history code (Z87.442) depends on confirmation status:
- If the patient reports symptoms consistent with stone passage (renal colic, hematuria, dysuria) but has not had confirmatory imaging, code as N20.0 or N20.9 to reflect active disease until proven otherwise 1, 3
- Patient self-report of stone passage is insufficient for using the history code without imaging confirmation, as stones may remain in the collecting system 4
- Follow-up imaging (ultrasound or low-dose CT) should be performed to confirm complete stone clearance before transitioning to history code 4, 3
Important Coding Pitfalls
Do not prematurely use the history code (Z87.442):
- Approximately 38% of patients with presumed passed stones may have residual fragments requiring intervention 4
- ICD-9 coding studies showed that administrative codes cannot reliably distinguish between renal and ureteral calculi (76% of ureteral stones were miscoded), so err on the side of the more general codes when uncertain 2
Additional codes to consider:
- R31.0 (Gross hematuria) or R31.9 (Hematuria, unspecified) - Add if blood in urine is documented 1
- R10.9 (Unspecified abdominal pain) or N23 (Unspecified renal colic) - Add if patient reports flank or groin pain 1, 3
Documentation Requirements
- Document the patient's specific symptoms (pain location, hematuria, timing) to support the code selection 1
- Note any prior stone history, as recurrence risk is 50% within 5-7 years, which justifies continued active disease coding until clearance is confirmed 4, 3
- Record whether imaging has been performed and results, as this determines appropriate code transition from active to history 4, 3