E20.810 ICD-10-CM Code: Autosomal dominant hypocalcemia
E20.810 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)
E20.810
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAutosomal dominant hypocalcemia
A rare inherited condition where low calcium levels in the blood are caused by an autosomal dominant genetic mutation affecting calcium regulation.
Buddy Insight
E20.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
MappedHCC 23
RAF 0.194
ACA/HHS
MappedHCC 30
Varies by metal level
ESRD/PACE
MappedHCC 23
RAF 0.036
RXHCC
MappedHCC 43
RAF 0.063
Code Book Path
Inclusion Terms
Official- Autosomal dominant hypocalcemia type 1 (ADH1)
- Autosomal dominant hypocalcemia type 2 (ADH2)
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for E20.810 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for E20.810 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for E20.810 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for E20.810 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for E20.810 in this effective period.
Code Also
Official- , if applicable, any associated conditions, such as:
- calculus of kidney (N20.0)
- chronic kidney disease (N18.-)
- respiratory distress (J80, R06.-)
- seizure disorder (G40.-, R56.9)
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 E20.810 an HCC code?
Yes. E20.810 maps to Other Significant Endocrine and Metabolic Disorders under the V24 model but is not retained in V28.
- Code
- E20.810
- Description
- Autosomal dominant hypocalcemia
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
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 E20.810 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for E20.810
For E20.810 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 E20.810 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
E20.810 is the ICD-10-CM diagnosis code for autosomal dominant hypocalcemia. A rare inherited condition where low calcium levels in the blood are caused by an autosomal dominant genetic mutation affecting calcium regulation. E20.810 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).
Under the older CMS-HCC V24 model, E20.810 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 specific genetic subtype; ensure genetic testing or family history documentation supports this diagnosis. Because E20.810 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 E20.810 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a specific genetic subtype; ensure genetic testing or family history documentation supports this diagnosis
- •Code separately from other forms of hypoparathyroidism as this represents a distinct genetic etiology
Clinical Significance
E20.810 identifies autosomal dominant hypocalcemia, a genetic disorder caused by activating mutations in the calcium-sensing receptor gene, leading to inappropriate suppression of parathyroid hormone secretion. Patients present with chronic hypocalcemia and relative hypercalciuria, distinguishing this condition from other forms of hypoparathyroidism and requiring specialized management to avoid nephrocalcinosis.
Documentation Requirements
- ✓Documentation must include the genetic diagnosis or strong clinical suspicion of autosomal dominant hypocalcemia with confirmatory genetic testing.
- ✓Laboratory findings including low parathyroid hormone, hypocalcemia, and inappropriately normal or elevated urinary calcium excretion should be documented.
- ✓Family history is important.