E21.2 ICD-10-CM Code: Other hyperparathyroidism
E21.2 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Disorders of other endocrine glands (E20-E35)
E21.2
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther hyperparathyroidism
Elevated parathyroid hormone and calcium levels due to causes other than primary gland disease or secondary causes, or when the specific type is not clearly identified.
Buddy Insight
Other hyperparathyroidism captures tertiary hyperparathyroidism and other atypical forms where the parathyroid glands become autonomously overactive, often after prolonged secondary stimulation.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 030
Code-level coefficient reference
ESRD/PACE
MappedHCC 23
Code-level coefficient reference
RXHCC
MappedHCC 43
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Tertiary hyperparathyroidism
Excludes 2
Official- familial hypocalciuric hypercalcemia (E83.52)Inherited from E21
Related Codes
Includes
OfficialNo Includes notes are included in this display for E21.2. Check the code and parent instructions in the Code Book.
Excludes 1
Official- transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E20-E35, E21
- galactorrhea (N64.3)Inherited from E00-E89, E20-E35, E21
- gynecomastia (N62)Inherited from E00-E89, E20-E35, E21
- adult osteomalacia (M83.-)Inherited from E00-E89, E20-E35, E21
- ectopic hyperparathyroidism (E34.2)Inherited from E00-E89, E20-E35, E21
- hungry bone syndrome (E83.81)Inherited from E00-E89, E20-E35, E21
- infantile and juvenile osteomalacia (E55.0)Inherited from E00-E89, E20-E35, E21
Code First
OfficialNo Code First sequencing instructions are included in this display for E21.2. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for E21.2. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for E21.2. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 E21.2 an HCC code?
E21.2 is not in the CMS-HCC V28 or V24 community payment model. E21.2 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E21.2 also appears in the HHS-HCC commercial risk model (HCC 030 (HHS-HCC 030 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping.
- Code
- E21.2
- Description
- Other hyperparathyroidism
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work E21.2 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for E21.2
For E21.2, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
E21.2 is the ICD-10-CM diagnosis code for other hyperparathyroidism. Elevated parathyroid hormone and calcium levels due to causes other than primary gland disease or secondary causes, or when the specific type is not clearly identified. E21.2 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering disorders of other endocrine glands (e20-e35).
E21.2 has no mapping under the CMS-HCC V28 or V24 community payment models. E21.2 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E21.2 also appears in the HHS-HCC commercial risk model (HCC 030 (HHS-HCC 030 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.
Use this code when hyperparathyroidism exists but does not fit clearly into primary or secondary categories.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E21.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Other hyperparathyroidism captures tertiary hyperparathyroidism and other atypical forms where the parathyroid glands become autonomously overactive, often after prolonged secondary stimulation. Tertiary disease commonly develops in patients with long-standing chronic kidney disease, even after transplant, when glands fail to regress.
Documentation Requirements
- ✓Document the specific type of hyperparathyroidism (tertiary or other specified form), history of prior secondary hyperparathyroidism, surgical history, calcium and parathyroid hormone levels, and clinical rationale for this classification.
Excludes 2, Not included here, may code separately
- familial hypocalciuric hypercalcemia (E83.52)