Stone analysis billed without stone passage (Updated for 2026)

Common Causes for U15

Denials with code U15 typically happen for the following specific reasons:

• Billing calculus analysis (CPT 82330 or 82331) without an associated surgical procedure code for stone retrieval (such as lithotripsy or ureteroscopy) in the patient's recent history.
• Failure to document spontaneous stone passage at home and the subsequent physical collection of the specimen by the clinic in the medical record.
• Coding errors where the diagnosis code for calculus (e.g., N20.0) is missing, or the specimen source is not clearly specified in the laboratory order.
• Incomplete clinical documentation regarding how the stone specimen was obtained, leaving the payer with no record of stone passage or extraction.

How to Prevent U15 Denials

To avoid receiving this denial in the future, implement these specific checks:

• Establish front-end billing edits that cross-reference laboratory calculus analysis codes with either a stone retrieval procedure or a documented spontaneous passage diagnosis code.
• Ensure the medical record explicitly documents the physical receipt of the stone specimen from the patient, including the date and method of spontaneous passage.
• Coordinate coding between the performing laboratory and the ordering urologist to align billing timelines and document physical specimen capture.
• Implement template-driven documentation in EHRs for stone-related visits, requiring providers to explicitly state if a stone was recovered and sent for analysis.

Appeal Letter Template for U15

If you believe this claim was denied incorrectly, you can use the following template to submit an appeal.

[Your Practice Header]
[Date]

[Payer Name]
[Appeals Department Address]

RE: Appeal for Claim [Claim Number]
Patient: [Patient Name]
ID: [Patient ID]
Date of Service: [Date]
Denial Code: U15 - Stone analysis billed without stone passage

Dear Appeals Department,

I am writing to appeal the denial of the above-referenced claim, which was denied with code U15: "Stone analysis billed without stone passage".

We are appealing the denial of CPT code 82330 (Calculus analysis; quantitative chemical). AMA CPT guidelines state that calculus analysis is appropriate when a physical specimen is processed and analyzed by the laboratory. In this case, as detailed in the attached clinical documentation, the patient spontaneously passed the stone at home and physically presented the specimen to our clinic for analysis. The medical record clearly establishes the existence, receipt, and laboratory analysis of the physical specimen, rendering a concurrent surgical extraction procedure unnecessary for this service to be medically necessary and complete. We respectfully request that you review the attached pathology report and clinical notes confirming specimen receipt and reverse this denial.

Attached please find:
1. A copy of the original claim.
2. The relevant medical records supporting the service.
3. [Any other supporting documents].

We respectfully request that you reprocess this claim for payment.

Sincerely,

[Your Name]
[Title]
[Practice Name]