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N25.81 ICD-10-CM Code: Secondary hyperparathyroidism of renal origin

N25.81 is not a CMS-HCC payment code. MEAT criteria · RAF calculator · free HCC coding tools

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FY 2026 Apr update / Diseases of the genitourinary system (N00-N99) / Other disorders of kidney and ureter (N25-N29)

N25.81

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Secondary hyperparathyroidism of renal origin

Overactive parathyroid glands that develop as a result of kidney disease and impaired calcium regulation.

Buddy the Bee presenting code insight

Buddy Insight

Secondary hyperparathyroidism of renal origin represents overactive parathyroid glands due to chronic kidney disease and disrupted calcium-phosphorus metabolism.

CMS-HCC V28

N/A

—

Not mapped

CMS-HCC V24

HCC 23

RAF 0.194

ACA/HHS

HCC 30

Varies by metal level

ESRD/PACE

HCC 23

RAF 0.036

RXHCC

HCC 43

RAF 0.063

Code Book Path

Official
N25Disorders resulting from impaired renal tubular function
N25.8Other disorders resulting from impaired renal tubular function
N25.81Secondary hyperparathyroidism of renal origin

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for N25.81 in this effective period.

Excludes 2

Official
  • metabolic disorders classifiable to E70-E88

Related Child Codes

Official
N25.89Other disorders resulting from impaired renal tubular function

Includes

Official

ICD-10-CM does not list Includes notes for N25.81 in this effective period.

Excludes 1

Official
  • secondary hyperparathyroidism, non-renal (E21.1)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for N25.81 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for N25.81 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for N25.81 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Secondary hyperparathyroidism clearly documented
Renal origin specifically identified and documented
Elevated parathyroid hormone (PTH) levels documented
Underlying chronic kidney disease documented and coded

MEAT Support

HCC Buddy guidance
Secondary hyperparathyroidism clearly documented
Renal origin specifically identified and documented
Elevated parathyroid hormone (PTH) levels documented
Underlying chronic kidney disease documented and coded

Audit Caution

HCC Buddy guidance
Using general secondary hyperparathyroidism codes when renal origin is documented
Not coding the underlying chronic kidney disease separately
Confusing with primary hyperparathyroidism
Failing to specify the renal origin when documented

Common Mistakes

HCC Buddy guidance
E21.1 — Secondary hyperparathyroidism, not elsewhere classified (not specifically renal)
E21.0 — Primary hyperparathyroidism (primary parathyroid disease)
N25.0 — Renal osteodystrophy (bone disease, not specifically PTH excess)
E83.30 — Disorder of phosphorus metabolism, unspecified (metabolic, not PTH)

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is N25.81 an HCC code?

Yes. N25.81 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.

Code
N25.81
Description
Secondary hyperparathyroidism of renal origin
HCC (V28)
No CMS-HCC V28 mapping
RAF
—
Billable
Yes
Payment year
2026

HCC Category Mapping

V24HCC 23, Other Significant Endocrine and Metabolic Disorders
0.194
ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders
0.036
RxHCCHCC 43, Other Significant Endocrine and Metabolic Disorders
0.063

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work N25.81 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for N25.81

For N25.81 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed N25.81 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

N25.81 is the ICD-10-CM diagnosis code for secondary hyperparathyroidism of renal origin. Overactive parathyroid glands that develop as a result of kidney disease and impaired calcium regulation. N25.81 sits in the ICD-10-CM chapter for diseases of the genitourinary system (n00-n99), within the section covering other disorders of kidney and ureter (n25-n29).

Under the older CMS-HCC V24 model, N25.81 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.194. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

This is a secondary condition caused by renal dysfunction; code the underlying kidney disease first. Because N25.81 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for N25.81 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This is a secondary condition caused by renal dysfunction; code the underlying kidney disease first
  • •Verify if parathyroid surgery was performed, which may affect coding

Clinical Significance

Secondary hyperparathyroidism of renal origin represents overactive parathyroid glands due to chronic kidney disease and disrupted calcium-phosphorus metabolism. This condition indicates CKD-mineral bone disorder requiring specialized management to prevent bone disease and cardiovascular complications associated with elevated PTH levels.

Documentation Requirements

  • ✓Secondary hyperparathyroidism clearly documented
  • ✓Renal origin specifically identified and documented
  • ✓Elevated parathyroid hormone (PTH) levels documented
  • ✓Underlying chronic kidney disease documented and coded
  • ✓Abnormal calcium, phosphorus, or vitamin D levels
  • ✓Treatment plan for hyperparathyroidism and underlying CKD
  • ✓Monitoring schedule for PTH, calcium, and phosphorus levels

Excludes 1, Do NOT code together

  • secondary hyperparathyroidism, non-renal (E21.1)

Excludes 2, Not included here, may code separately

  • metabolic disorders classifiable to E70-E88

Commonly Confused Codes

  • •E21.1: Secondary hyperparathyroidism, not elsewhere classified (not specifically renal)
  • •E21.0: Primary hyperparathyroidism (primary parathyroid disease)
  • •N25.0: Renal osteodystrophy (bone disease, not specifically PTH excess)
  • •E83.30: Disorder of phosphorus metabolism, unspecified (metabolic, not PTH)

Child Codes

N25.81Secondary hyperparathyroidism of renal origin
N25.89Other disorders resulting from impaired renal tubular function

Code Hierarchy

└N25Disorders resulting from impaired renal tubular function└N25.8Other disorders resulting from impaired renal tubular function└N25.81Secondary hyperparathyroidism of renal origin
└N25.81Secondary hyperparathyroidism of renal origin

Because N25.81 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

Work N25.81 in HCC Buddy

Open N25.81 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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