ICD-10 Code N28.0: Ischemia and infarction of kidney

Key Takeaways

ICD-10 Code N28.0 is the billable diagnosis code for ischemia and infarction of kidney, valid for fiscal year 2026 (October 1, 2025 through September 30, 2026).

Five conditions map to N28.0 under Applicable To: renal artery embolism, obstruction, occlusion, thrombosis, and renal infarct.

N28.0 carries Excludes1 restrictions that prevent simultaneous coding with certain vascular conditions, making exclusion review mandatory before submission.

Pabau’s claims management software helps nephrology and internal medicine practices submit N28.0 accurately and track denials tied to missing documentation.

ICD-10 Code N28.0 is the official ICD-10-CM diagnosis code for ischemia and infarction of kidney. It is a billable/specific code, meaning it meets the required level of specificity for HIPAA-covered transaction submission.

The code sits within chapter 14 (Diseases of the genitourinary system), block N25-N29 (Other disorders of kidney and ureter), under category N28 (Other disorders of kidney and ureter, not elsewhere classified).

Code details at a glance

The table below provides a quick-reference summary for ICD-10 Code N28.0, including its validity period, hierarchical position, and billable status.

The CMS ICD-10 codes page publishes the annual tabular list updates. Always confirm a code’s validity against the current fiscal year file before submission, particularly after October 1 transitions.

Applicable To: Conditions included under N28.0

The ICD-10-CM “Applicable To” note functions as a built-in crosswalk. When the physician documents any of the five conditions listed below, N28.0 is the correct code, even if the note uses a synonym rather than the official descriptor “ischemia and infarction of kidney.” Understanding this ischemia and infarction of kidney ICD-10 mapping prevents unnecessary queries back to the physician.

• Renal artery embolism: occlusion caused by an embolus traveling to the renal artery, often originating from cardiac sources such as atrial fibrillation or mural thrombus
• Renal artery obstruction: any mechanical blockage reducing or stopping arterial flow to the kidney, whether thrombotic, embolic, or compressive in origin
• Renal artery occlusion: complete closure of the renal artery lumen; may be acute or chronic and is a recognized cause of renovascular hypertension
• Renal artery thrombosis: in-situ clot formation within the renal artery, distinguishable from embolism by its local pathogenesis rather than migration from a distant site
• Renal infarct: necrosis of kidney tissue resulting from sustained ischemia; the downstream consequence of the vascular events listed above

When documentation specifies the mechanism (thrombosis vs embolism), note that distinction in the medical record. It does not change the code, but it supports medical necessity and audit defense. For coders working on renal infarction ICD-10 code selection, all five conditions resolve to N28.0 with no additional character required.

What is not covered: Excludes1 conditions

Excludes1 means the listed conditions cannot be coded at the same encounter as N28.0. They represent mutually exclusive diagnoses, not additional ones. Submitting both N28.0 and an Excludes1 code on the same claim will generate an edit, and the claim will likely reject.

The N28.0 Excludes1 conditions include certain atherosclerotic and renovascular disease codes that have their own specific classification. Before assigning N28.0, verify that the clinical picture does not fall under an excluded category. When the documentation is ambiguous, a physician query is the appropriate next step, not a coding assumption.

Coders should review the full Excludes1 list as published in the CDC/NCHS ICD-10-CM web tool for the current fiscal year. The list is updated annually and should be confirmed against the FY 2026 tabular, not from memory or a prior-year reference.

Clinical description: Renal ischemia and infarction

Renal ischemia occurs when arterial blood flow to one or both kidneys falls below the threshold needed to maintain cellular function. Sustained ischemia leads to infarction, the irreversible necrotic death of renal parenchyma.

Acute renal infarction can present like renal colic or flank pain, leading to initial misdiagnosis and coding under a pain code rather than the underlying vascular event.

Common precipitating causes include atrial fibrillation (cardioembolic source), hypercoagulable states, trauma to the renal artery, and aortic dissection extending to the renal vessels. Patients treated at functional medicine practices for metabolic comorbidities may present with chronic renal ischemia superimposed on baseline renovascular disease.

For coding purposes, the clinical distinction between acute and chronic presentation does not generate a different code under N28.0. What matters for defensible coding is that the physician explicitly documents the diagnosis of renal ischemia or infarction, or one of the five Applicable To conditions, rather than only symptoms such as flank pain or hematuria.

The WHO ICD-10 browser provides the international classification context for this condition. The U.S. ICD-10-CM version applies clinical modifications relevant to domestic billing, which is why the Applicable To list and Excludes1 annotations exist in the CM version but not in the base WHO classification.

Always reference the current ICD-10-CM tabular rather than the international version for domestic claims.

How to document renal infarction for accurate ICD-10 coding

Missing documentation is the primary cause of N28.0 denials. The physician note must establish a causal connection between the vascular event and the kidney, not merely list symptoms. The following steps represent the documentation standard that supports N28.0 coding without additional physician queries.

1. State the diagnosis explicitly: use “renal infarction,” “renal artery thrombosis,” “renal artery embolism,” or another Applicable To term. Avoid phrases like “suspect renal ischemia” or “rule out renal infarct,” which do not meet outpatient coding requirements for confirmed diagnoses.
2. Document laterality where known: while N28.0 does not require a laterality modifier, documenting left, right, or bilateral supports medical record integrity and downstream imaging correlation.
3. Identify the underlying cause: document whether the event is embolic (and the embolic source, if known) or thrombotic. This is not required to assign N28.0, but it matters for complication tracking and may affect sequencing when a cardiovascular code is principal.
4. Distinguish from symptoms: if flank pain or hematuria is also present, those symptom codes are generally not separately reportable once the underlying diagnosis is confirmed. The structured patient record management workflow should capture confirmed diagnoses, not working differentials, as the primary encounter documentation.
5. Note acute vs. chronic status: while N28.0 does not differentiate, notation of acute infarction vs. chronic ischemic change informs severity documentation for risk adjustment.

Practices using digital clinical documentation tools can build structured note templates that prompt clinicians to capture each element above, reducing the back-and-forth between coders and providers that delays claim submission.

ICD-10 coding guidelines for N28.0

The ICD-10-CM Official Guidelines for Coding and Reporting, maintained jointly by the National Center for Health Statistics (NCHS) and the Centers for Medicare and Medicaid Services (CMS), govern how N28.0 is sequenced and applied. Two guidelines are particularly relevant.

Sequencing: Principal vs. secondary diagnosis

When renal infarction results from a cardiac condition (such as atrial fibrillation causing an embolus), sequencing depends on the reason for the encounter. If the admission or outpatient visit is primarily to evaluate or treat the cardiac condition, that condition is the principal diagnosis. N28.0 becomes a secondary code reflecting the complication.

Conversely, if the renal event is the primary focus of the encounter, N28.0 sequences first. The same principal-versus-secondary logic applies to related renal-cardiovascular pairings, such as I15.1, where the reason for the encounter determines which code leads.

Using a compliance documentation checklist as part of the coding workflow helps keep sequencing decisions consistent across cases like these.

Etiology/manifestation coding

N28.0 does not currently require a mandatory etiology/manifestation pairing in the ICD-10-CM tabular. However, if the renal infarction is documented as a manifestation of a systemic condition, such as polyarteritis nodosa or antiphospholipid syndrome, the systemic condition should be coded first per the etiology/manifestation convention.

Lab work such as a C4 complement blood test can help confirm an autoimmune cause before that sequencing decision is made.

The AAPC Codify ICD-10-CM lookup provides annotation notes for each code that flag these conventions. Cross-referencing against a current coding tool catches manifestation requirements that are easy to miss when working from memory.

Reduce coding denials with streamlined documentation

Pabau helps nephrology and internal medicine practices build structured clinical notes, track claims, and manage documentation workflows, so coders and providers stay aligned from the first encounter.

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Related ICD-10-CM codes

Understanding the N28 category context helps coders choose between adjacent codes when the clinical picture is more complex than a simple renal infarction. The table below maps the most commonly compared codes and when each applies.

For internal medicine practices managing renal vascular diagnoses across multiple specialties, maintaining a working crosswalk of related codes reduces the time spent on physician queries and improves first-pass claim rates.

CPT codes commonly billed with ICD-10 Code N28.0

The table below maps the CPT codes most commonly billed alongside N28.0, based on the typical renal infarction workup and management pathway.

Pabau’s claims management software allows practices to build code sets pairing N28.0 with the appropriate CPT procedures, reducing the manual effort of assembling claims for complex renal vascular encounters. This also supports consistency when multiple providers in a group are coding the same encounter type.

Conclusion

Renal ischemia and infarction is a high-stakes diagnosis that coders often encounter in nephrology, internal medicine, and interventional radiology billing. Getting the code right the first time means knowing the Applicable To list, reviewing Excludes1 before submission, documenting the confirmed diagnosis rather than symptoms, and sequencing correctly when a cardiac etiology is present.

Pabau’s practice management software brings clinical documentation and claims workflows together so coders and clinicians stay aligned throughout the billing cycle. If you want to see how it handles complex diagnosis coding and denial tracking for specialty practices, book a demo.

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Frequently asked questions

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