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E80.20 ICD-10-CM Code: Unspecified porphyria

E80.20 maps to CMS-HCC V28 50. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupE80.20

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Metabolic disorders (E70-E88)

E80.20

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

Unspecified porphyria

A metabolic disorder affecting heme production with unspecified type, potentially causing abdominal pain, neurological symptoms, or skin problems.

Buddy the Bee presenting code insight

Buddy Insight

Unspecified porphyria is used when a porphyria diagnosis is established but the specific type has not been determined.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 50

Coefficient HCC 50: 0.648 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 029

Code-level coefficient reference

ESRD/PACE

HCC 23

Code-level coefficient reference

RXHCC

HCC 43

Code-level coefficient reference

Code Book Path

Official
E80Disorders of porphyrin and bilirubin metabolismE80.2Other and unspecified porphyriaE80.20Unspecified porphyria

Inclusion Terms

Official
  • Porphyria NOS

Excludes 2

Official
  • Ehlers-Danlos syndromes (Q79.6-)Inherited from E70-E88

Related Codes

Official
E80.21Acute intermittent (hepatic) porphyriaE80.29Other porphyria

Includes

Official
  • defects of catalase and peroxidaseInherited from E80

Excludes 1

Official
  • transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E70-E88
  • androgen insensitivity syndrome (E34.5-)Inherited from E00-E89, E70-E88
  • congenital adrenal hyperplasia (E25.0)Inherited from E00-E89, E70-E88
  • hemolytic anemias attributable to enzyme disorders (D55.-)Inherited from E00-E89, E70-E88
  • Marfan syndrome (Q87.4-)Inherited from E00-E89, E70-E88
  • 5-alpha-reductase deficiency (E29.1)Inherited from E00-E89, E70-E88

Code First

Official

No Code First sequencing instructions are included in this display for E80.20. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for E80.20. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for E80.20. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Provider diagnosis confirming porphyria
Porphyrin analysis results (urine, fecal, or plasma) even if type-indeterminate
Clinical presentation: cutaneous, neurovisceral, or both
Reason specific type is not identified (initial presentation, workup in progress, atypical pattern)

MEAT Support

HCC Buddy guidance
Provider diagnosis confirming porphyria
Porphyrin analysis results (urine, fecal, or plasma) even if type-indeterminate
Clinical presentation: cutaneous, neurovisceral, or both
Reason specific type is not identified (initial presentation, workup in progress, atypical pattern)

Audit Caution

HCC Buddy guidance
Using E80.20 long-term when diagnostic testing could identify the specific porphyria type
Not querying the provider when porphyrin profiles in the chart suggest a specific type
Confusing elevated porphyrins (a lab finding) with a porphyria diagnosis (a clinical disease)
Starting treatment before identifying the type — treatment for one porphyria may worsen another

Common Mistakes

HCC Buddy guidance
E80.0 — Hereditary erythropoietic porphyria: use when this specific type is confirmed
E80.1 — Porphyria cutanea tarda: use when PCT is specifically diagnosed
E80.21 — Acute intermittent porphyria: use when AIP is confirmed
E80.29 — Other porphyria: for variegate porphyria, hereditary coproporphyria, or other named types

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 E80.20 an HCC code?

Yes. E80.20 (Unspecified porphyria) maps to HCC 50, Amyloidosis, Porphyria, and Other Specified Metabolic Disorders under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.648. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: E80.20 is billable and maps to V28 HCC 50, Amyloidosis, Porphyria, and Other Specified Metabolic Disorders. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
E80.20
Description
Unspecified porphyria
HCC (V28)
HCC 50 — Amyloidosis, Porphyria, and Other Specified Metabolic Disorders
RAF reference coefficient
0.648
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 50, Amyloidosis, Porphyria, and Other Specified Metabolic Disorders
0.648
ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders
Not separately weighted
RxHCCHCC 43, Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders
Not separately weighted

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 E80.20 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E80.20

For E80.20, 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

E80.20 is the ICD-10-CM diagnosis code for unspecified porphyria. A metabolic disorder affecting heme production with unspecified type, potentially causing abdominal pain, neurological symptoms, or skin problems. E80.20 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

Under the CMS-HCC V28 risk adjustment model, E80.20 maps to Amyloidosis, Porphyria, and Other Specified Metabolic Disorders (HCC 50) with a source-labeled community, non-dual, aged reference coefficient of 0.648. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Use this code only when the specific type of porphyria cannot be determined. For E80.20, 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. 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, source-labeled coefficient references, and MEAT documentation criteria for E80.20 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Use this code only when the specific type of porphyria cannot be determined
  • •Attempt to obtain more specific diagnosis information for proper code assignment

Clinical Significance

Unspecified porphyria is used when a porphyria diagnosis is established but the specific type has not been determined. Given that different porphyrias require fundamentally different treatments (phlebotomy for PCT, hemin for acute porphyrias), this code should be transitional and prompt further diagnostic workup to identify the exact type.

Documentation Requirements

  • ✓Provider diagnosis confirming porphyria
  • ✓Porphyrin analysis results (urine, fecal, or plasma) even if type-indeterminate
  • ✓Clinical presentation: cutaneous, neurovisceral, or both
  • ✓Reason specific type is not identified (initial presentation, workup in progress, atypical pattern)
  • ✓Plan for further diagnostic testing to determine porphyria type
  • ✓Acute management if symptomatic

Commonly Confused Codes

  • •E80.0: Hereditary erythropoietic porphyria: use when this specific type is confirmed
  • •E80.1: Porphyria cutanea tarda: use when PCT is specifically diagnosed
  • •E80.21: Acute intermittent porphyria: use when AIP is confirmed
  • •E80.29: Other porphyria: for variegate porphyria, hereditary coproporphyria, or other named types
  • •R82.1: Porphyrinuria: for abnormal urine porphyrins without confirmed porphyria diagnosis

Child Codes

E80.20Unspecified porphyria
HCC 50
E80.21Acute intermittent (hepatic) porphyria
HCC 50
E80.29Other porphyria
HCC 50

Code Hierarchy

└E80Disorders of porphyrin and bilirubin metabolism└E80.2Other and unspecified porphyria└E80.20Unspecified porphyria
└E80.20Unspecified porphyria

Also searched as

  • E80 20
  • E8020

For E80.20, 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.

E80.20 maps to CMS-HCC V28 category 50, Amyloidosis, Porphyria, and Other Specified Metabolic Disorders. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for E80.20. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

Work E80.20 in HCC Buddy

Open E80.20 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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