N25.0

🧬 ICD-10 CM N25.0 — Renal Osteodystrophy

Billable Code Confirmed

ICD-10 CM N25.0 is a complete, 4-character billable code under category N25 and requires no additional digits for claim submission.¹² It is valid for the FY2026 code set (October 1, 2025 – September 30, 2026) and is classified as a chronic condition.¹³

Non-Billable Parent Codes

N25 (Disorders resulting from impaired renal tubular function) is a non-billable category header — it lacks the fourth-character detail needed to specify which tubular disorder is present and must never be reported alone.²³ Providers documenting only “renal tubular disorder” without further specificity will force the coder back to the provider for clarification before N25.0 can be assigned.

Clinical Context

Selection of N25.0 depends on documentation of bone disease specifically attributable to impaired mineral metabolism from chronic kidney disease, distinguishing it from isolated secondary hyperparathyroidism (N25.81) or unspecified tubular dysfunction (N25.9).¹⁴

Code Classification

ICD-10 CM N25.0 is a diagnosis code used to report a chronic metabolic bone manifestation of renal disease; it is not a procedure code and carries no laterality component.

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🔍 Code Description

Renal osteodystrophy describes the spectrum of bone mineralization and remodeling abnormalities that develop as kidney function declines, most often in patients with advanced N18.4 or dialysis-dependent N18.6. As the kidneys lose the ability to activate vitamin D and excrete phosphate, patients develop hyperphosphatemia, hypocalcemia, and compensatory secondary hyperparathyroidism, which together drive abnormal bone turnover ranging from high-turnover fibrosis to low-turnover adynamic bone disease.¹⁴¹⁵ Clinically this condition is often documented as “CKD-mineral and bone disorder” (CKD-MBD), a broader umbrella term that includes N25.0 as its skeletal component alongside vascular calcification and biochemical abnormalities.

Coders should watch for documentation terms such as azotemic osteodystrophy, renal rickets (in pediatric patients), or Sagliker syndrome, all of which map to N25.0 as inclusion terms.¹³ The condition is frequently comorbid with N18.6 and long-term dialysis, and its presence should prompt review of parathyroid hormone, calcium, and phosphorus lab values to support the diagnosis for both clinical validity and DRG assignment. Because renal osteodystrophy is chronic and progressive, it is commonly captured across multiple inpatient encounters rather than a single isolated admission.

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🌳 Code Tree / Hierarchy

N25 Disorders resulting from impaired renal tubular function ❌ Non-billable
│
├── N25.0 Renal osteodystrophy ◀ THIS CODE ✅ Billable
├── N25.1 Nephrogenic diabetes insipidus ✅ Billable
│
├── N25.8 Other disorders resulting from impaired renal tubular function ❌ Non-billable
│   │
│   ├── N25.81 Secondary hyperparathyroidism of renal origin ✅ Billable
│   └── N25.89 Other disorders resulting from impaired renal tubular function ✅ Billable
│
└── N25.9 Disorder resulting from impaired renal tubular function, unspecified ✅ Billable

Specificity Matters

Reporting N25.0 instead of the non-billable parent N25 or the vague N25.9 signals a confirmed mineral bone disorder rather than an unspecified tubular defect, which supports medical necessity for bone density studies and PTH-lowering therapy.²³

Tip

Always cross-check whether the provider intends renal osteodystrophy (a bone disease) versus secondary hyperparathyroidism alone (N25.81) — the two frequently coexist and both may be reportable when separately documented.¹⁴

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✅ Includes

• Azotemic osteodystrophy — bone disease terminology tied directly to nitrogenous waste retention in kidney failure.¹³
• Phosphate-losing tubular disorders — tubular phosphate wasting contributing to the same bone mineralization defect.¹³
• Renal rickets — the pediatric presentation of renal osteodystrophy, involving growth plate abnormalities.¹³
• Renal short stature — growth impairment in children secondary to chronic renal bone disease.¹³

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❌ Excludes

Excludes 1

No Excludes1 notes are published for N25.0 in the **FY2026 ICD-10-CM Tabular List.**²³

Excludes 2

• E70- — Disorders of aromatic amino-acid metabolism; this is a distinct inherited metabolic pathway disorder and may be coded together with N25.0 when both are clinically present.¹⁰
• E88- — Other and unspecified metabolic disorders; represents metabolic conditions outside the renal-bone axis and can be reported concurrently with N25.0 when documented separately.¹⁰

Danger

A common error is assuming Excludes2 codes E70- and E88- can never be reported with N25.0 — since these are Excludes2 (not Excludes1), both the metabolic disorder and renal osteodystrophy may be coded together if the patient truly has both conditions.¹⁰

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📋 Clinical Overview

Renal Osteodystrophy vs. Secondary Hyperparathyroidism

Distinguishing N25.0 from N25.81 hinges on whether the documentation supports an actual bone disease process versus an isolated hormonal/biochemical abnormality. Both conditions frequently coexist in CKD patients, and correct sequencing depends on which manifestation drove the clinical workup or treatment during the admission.

Feature	N25.0	N25.81	N18.6
Underlying process	Bone mineralization/remodeling defect from CKD	Elevated PTH driven by renal phosphate/calcium imbalance	End-stage renal failure requiring dialysis
Typical documentation	”Renal osteodystrophy,” “CKD-MBD,” bone pain/fracture	”Secondary hyperparathyroidism of renal origin,” elevated PTH	”ESRD,” dialysis-dependent
Coding relationship	Often coexists with N25.81 as manifestation	Often the biochemical driver of N25.0	Frequently the etiology requiring both above codes

Important

A CDI trigger should fire whenever a provider documents “CKD-MBD” without specifying whether bone disease (N25.0) or hyperparathyroidism (N25.81) is present, since both carry distinct coding and clinical management implications.

Manifestations & Symptom Burden

• Bone pain and fractures — weakened bone architecture increases fracture risk, particularly in dialysis-dependent patients.
• Growth retardation — seen in pediatric renal rickets presentations.
• Skeletal deformities — bowing of long bones and vertebral changes in advanced disease.
• Muscle weakness — associated with vitamin D deficiency and calcium dysregulation.
• Vascular and soft-tissue calcification — part of the broader CKD-MBD spectrum, though coded separately when documented.

Tip

Manifestation-level symptoms (fractures, bone pain) should be coded additionally when they represent a distinct treatable condition rather than folded silently into N25.0.

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💰 HCC Risk Adjustment

ICD-10 CM N25.0 does not map to a payment HCC under CMS-HCC V24 or the fully phased-in V28 model for CY2026, meaning it carries no direct community Medicare Advantage RAF weight on its own.⁵ It does map under the Part D RxHCC model to HCC 87 (Osteoporosis, Vertebral and Pathological Fractures), reflecting fracture risk associated with renal bone disease. Coders working in risk-adjustment settings should ensure the underlying CKD stage or ESRD code is captured alongside N25.0, since those diagnoses (not N25.0 itself) drive the primary community risk score.

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🏥 MS-DRG Assignment

ICD-10 CM N25.0 groups to MDC 11 (Diseases & Disorders of the Kidney & Urinary Tract) and, when reported as principal diagnosis, defaults to DRG 698 (with MCC), DRG 699 (with CC), or DRG 700 (without CC/MCC) depending on secondary diagnosis severity.³⁴ Sequencing should reflect the actual reason for admission — if the encounter is primarily for dialysis management or ESRD, N18.6 may be more appropriate as principal with N25.0 sequenced as a secondary/manifestation diagnosis. Because N25.0 appears on CMS’s list of principal diagnoses that can convert certain otherwise-qualifying secondary CC/MCC diagnoses to non-CC status, careful review of the full code set on the claim is needed to avoid unintentionally lowering DRG weight.²¹

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🔗 Related ICD-10-CM Codes

Same category (N25 family): N25.1, N25.81, N25.89, N25.9

Etiology / commonly paired codes: N18.2, N18.30, N18.4, N18.6, E83.52

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🛠️ Commonly Associated CPT Codes

• 77080 — Dual-energy X-ray absorptiometry (DXA), axial skeleton; used to assess bone mineral density loss from renal osteodystrophy.
• 83970 — Parathyroid hormone (PTH) assay; essential lab to confirm secondary hyperparathyroidism driving the bone disease.
• 82310 — Calcium, total; routine monitoring lab tied to CKD-MBD management.
• 84100 — Phosphorus (phosphate) level; tracks phosphate retention contributing to bone disease.
• 90999 — Unlisted dialysis procedure; may appear when dialysis management is documented alongside renal osteodystrophy in ESRD patients.
• 20225 — Bone biopsy, deep; occasionally performed to characterize turnover type (high vs. low) in ambiguous renal bone disease cases.

NCCI Bundling Considerations

Routine labs (PTH, calcium, phosphorus) drawn during the same encounter as a dialysis session are typically bundled into the dialysis facility fee and not separately billable in the outpatient dialysis setting. DXA scans and bone biopsies performed for renal osteodystrophy generally are not bundled with routine E/M visits and can be billed separately when medically necessary and properly documented.

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🔬 ICD-10-PCS Crosswalk

• 0PB00ZZ — Excision of thoracic vertebra, open approach; relevant when bone biopsy is performed to confirm renal osteodystrophy turnover subtype.
• 0P9330Z — Drainage of sternum with drainage device, percutaneous approach; used in select bone marrow/biopsy procedures related to metabolic bone workup.
• 5A1D00Z — Performance of urinary filtration, single, for dialysis in the ESRD setting frequently coexisting with renal osteodystrophy management.

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💊 Coding Scenarios and Examples

Scenario 1: A dialysis-dependent patient is admitted for management of worsening bone pain and elevated PTH, with imaging confirming renal osteodystrophy.

• Correct coding: N25.0, N18.6, Z99.2. Sequencing places renal osteodystrophy as principal since it is the reason for admission, with ESRD and dialysis status as secondary diagnoses. CDI note: confirm whether PTH elevation alone (N25.81) should also be separately captured.

Scenario 2: A pediatric patient with CKD stage 4 presents with growth failure and radiographic renal rickets.

• Correct coding: N25.0, N18.4. The bone manifestation (renal rickets, included under N25.0) is sequenced based on the focus of treatment; CKD stage 4 is coded as an additional diagnosis to reflect severity.

Scenario 3: An inpatient with ESRD on hemodialysis develops a pathologic fracture attributable to underlying renal bone disease.

• Correct coding: N25.0, N18.6, plus the appropriate pathologic fracture code from the M80-M84 range if documented. Sequencing depends on whether the fracture or the underlying renal bone disease prompted the admission; CDI clarification should confirm the causal link documented by the provider.

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⚠️ Coding Pitfalls and Tips

• Pitfall 1: Never report the non-billable parent N25 alone — always drill down to the fourth/fifth character such as N25.0.
• Pitfall 2: Do not automatically assume N25.0 and N25.81 are interchangeable; they represent different, though related, manifestations and may both be coded when separately documented.
• Pitfall 3: Remember that N25.0 carries no CMS-HCC V28 community payment weight, so it should not be relied upon alone for risk-adjustment revenue capture.
• Pitfall 4: Always verify the underlying CKD stage (N18.-) is documented and coded, since this drives both clinical accuracy and DRG/RAF impact.
• Pitfall 5: Excludes2 codes E70 and E88 may be reported together with N25.0 when clinically supported — don’t mistake this for an Excludes1 restriction.
• Pitfall 6:: Watch for “CKD-MBD” documentation without specificity; query the provider to determine whether bone disease, hyperparathyroidism, or both should be captured.

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📚 Sources

1. AAPC Codify, "ICD-10 Code for Renal osteodystrophy — N25.0," 2026. 2. ICD10Data.com, "2026 ICD-10-CM Diagnosis Code N25.0," 2026. 3. ICD10Data.com, "2026 ICD-10-CM Codes N25-," 2026. 4. icdlist.com, "ICD-10-CM Diagnosis Code N25.0 — Renal osteodystrophy," 2025. 5. hccbuddy.com, "2026 ICD-10-CM N25.0: Renal osteodystrophy," 2025. 6. icd10codingpro.com, "N25.0 — Renal osteodystrophy," FY2026. 7. CMS.gov, "ICD-10-CM/PCS MS-DRG v37.2 Definitions Manual," 2026. 8. icdcodes.ai, "Renal Osteodystrophy — ICD-10 Documentation Guidelines," 2025. 9. CodeMap, "MS-DRG 699 Diagnosis List," 2026.

_{Sources listed above correspond to superscript citations throughout this note. Verify all Medicare payment figures against your current CMS PFS Lookup tool and applicable MAC LCD prior to claim submission. Please use the latest AAPC/AHIMA Coding Books to verify each code within this note.}