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E88.01 ICD-10-CM Code: Alpha-1-antitrypsin deficiency

E88.01 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 · HCC Buddy coding tools

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Code lookupE88.01

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

E88.01

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

Alpha-1-antitrypsin deficiency

A genetic condition where the body doesn't produce enough alpha-1-antitrypsin, a protein that protects the lungs and liver from damage.

Buddy the Bee presenting code insight

Buddy Insight

Alpha-1-antitrypsin deficiency is a genetic condition predisposing patients to early-onset emphysema and liver disease.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 50

Code-level coefficient reference

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 40

Code-level coefficient reference

Code Book Path

Official
E88Other and unspecified metabolic disordersE88.0Disorders of plasma-protein metabolism, not elsewhere classifiedE88.01Alpha-1-antitrypsin deficiency

Inclusion Terms

Official
  • AAT deficiency

Excludes 2

Official
  • Ehlers-Danlos syndromes (Q79.6-)Inherited from E70-E88, E88.0
  • disorder of lipoprotein metabolism (E78.-)Inherited from E70-E88, E88.0

Related Codes

Official
E88.02Plasminogen deficiencyE88.09Other disorders of plasma-protein metabolism, not elsewhere classified

Includes

Official

No Includes notes are included in this display for E88.01. 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, E70-E88, E88, E88.0
  • androgen insensitivity syndrome (E34.5-)Inherited from E00-E89, E70-E88, E88, E88.0
  • congenital adrenal hyperplasia (E25.0)Inherited from E00-E89, E70-E88, E88, E88.0
  • hemolytic anemias attributable to enzyme disorders (D55.-)Inherited from E00-E89, E70-E88, E88, E88.0
  • Marfan syndrome (Q87.4-)Inherited from E00-E89, E70-E88, E88, E88.0
  • 5-alpha-reductase deficiency (E29.1)Inherited from E00-E89, E70-E88, E88, E88.0
  • histiocytosis X (chronic) (C96.6)Inherited from E00-E89, E70-E88, E88, E88.0
  • monoclonal gammopathy (of undetermined significance) (D47.2)Inherited from E00-E89, E70-E88, E88, E88.0
  • polyclonal hypergammaglobulinemia (D89.0)Inherited from E00-E89, E70-E88, E88, E88.0
  • Waldenström macroglobulinemia (C88.00)Inherited from E00-E89, E70-E88, E88, E88.0

Code First

Official

No Code First sequencing instructions are included in this display for E88.01. Check the code and parent instructions in the Code Book.

Use Additional

Official
  • codes for associated conditionsInherited from E88

Code Also

Official

No Code Also instructions are included in this display for E88.01. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Confirmed alpha-1-antitrypsin deficiency diagnosis
Alpha-1-antitrypsin serum level (typically < 11 micromol/L)
Genotype/phenotype documented (ZZ, SZ, MZ, etc.)
Associated conditions documented (emphysema, liver disease, panniculitis)

MEAT Support

HCC Buddy guidance
Confirmed alpha-1-antitrypsin deficiency diagnosis
Alpha-1-antitrypsin serum level (typically < 11 micromol/L)
Genotype/phenotype documented (ZZ, SZ, MZ, etc.)
Associated conditions documented (emphysema, liver disease, panniculitis)

Audit Caution

HCC Buddy guidance
Coding only the COPD/emphysema without identifying the underlying alpha-1-antitrypsin deficiency
Not recognizing that alpha-1 deficiency should be coded in addition to its pulmonary and hepatic manifestations
Missing the diagnosis in young patients with emphysema or unexplained liver disease
Confusing carrier status (MZ heterozygote) with clinical deficiency (ZZ homozygote)

Common Mistakes

HCC Buddy guidance
J43.9 — Emphysema, unspecified: may be caused by alpha-1 deficiency but does not capture the underlying genetic cause
J44.1 — Chronic obstructive pulmonary disease with acute exacerbation: COPD from any cause, does not specify alpha-1
K74.69 — Other cirrhosis of liver: may result from alpha-1 but does not capture the metabolic cause
E88.09 — Other disorders of plasma-protein metabolism: different protein metabolism disorders

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 E88.01 an HCC code?

Yes. E88.01 (Alpha-1-antitrypsin deficiency) 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: E88.01 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
E88.01
Description
Alpha-1-antitrypsin deficiency
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 40, Alpha-1-Antitrypsin Deficiency
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 E88.01 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E88.01

For E88.01, 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

E88.01 is the ICD-10-CM diagnosis code for alpha-1-antitrypsin deficiency. A genetic condition where the body doesn't produce enough alpha-1-antitrypsin, a protein that protects the lungs and liver from damage. E88.01 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, E88.01 maps to Amyloidosis, Porphyria, and Other Specified Metabolic Disorders (HCC 50) with a source-labeled community, non-dual, aged reference coefficient of 0.648. No V24 mapping is shown for E88.01; use the applicable model and payment year when reviewing the V28 mapping. 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 E88.01 when the provider wording supports alpha-1-antitrypsin deficiency. Check the FY2026 tabular notes and the full code path before the final code choice. For E88.01, 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 E88.01 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Use E88.01 when the provider wording supports alpha-1-antitrypsin deficiency. Check the FY2026 tabular notes and the full code path before the final code choice.
  • •For this DOS, capture the provider's current assessment and the care action documented for alpha-1-antitrypsin deficiency. Keep the checklist tied to the note.
  • •Do not swap E88.01 with E88.02. The FY2026 tabular describes E88.02 as plasminogen deficiency. Follow the documented detail.
  • •E88.01 maps to V28 HCC 50, Amyloidosis, Porphyria, and Other Specified Metabolic Disorders. The mapping does not replace the documentation review. The code still has to match the note.
  • •Ask Buddy to show the official notes for E88.01 or compare its code path with E88.02.

Clinical Significance

Alpha-1-antitrypsin deficiency is a genetic condition predisposing patients to early-onset emphysema and liver disease. It is significantly underdiagnosed, with many patients coded only for COPD without recognition of the underlying genetic cause. Capturing this code ensures appropriate augmentation therapy consideration and genetic counseling.

Documentation Requirements

  • ✓Confirmed alpha-1-antitrypsin deficiency diagnosis
  • ✓Alpha-1-antitrypsin serum level (typically < 11 micromol/L)
  • ✓Genotype/phenotype documented (ZZ, SZ, MZ, etc.)
  • ✓Associated conditions documented (emphysema, liver disease, panniculitis)
  • ✓Current treatment (augmentation therapy with IV alpha-1 proteinase inhibitor)
  • ✓Pulmonary function testing and liver function assessment

Commonly Confused Codes

  • •J43.9: Emphysema, unspecified: may be caused by alpha-1 deficiency but does not capture the underlying genetic cause
  • •J44.1: Chronic obstructive pulmonary disease with acute exacerbation: COPD from any cause, does not specify alpha-1
  • •K74.69: Other cirrhosis of liver: may result from alpha-1 but does not capture the metabolic cause
  • •E88.09: Other disorders of plasma-protein metabolism: different protein metabolism disorders

Child Codes

E88.01Alpha-1-antitrypsin deficiency
HCC 50
E88.02Plasminogen deficiency
E88.09Other disorders of plasma-protein metabolism, not elsewhere classified

Code Hierarchy

└E88Other and unspecified metabolic disorders└E88.0Disorders of plasma-protein metabolism, not elsewhere classified└E88.01Alpha-1-antitrypsin deficiency
└E88.01Alpha-1-antitrypsin deficiency

For E88.01, 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.

E88.01 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 E88.01. 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 E88.01 in HCC Buddy

Open E88.01 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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