ICD-10 E46
Billable / Specific HCC v28: 21 CCUnspecified protein-calorie malnutrition
About ICD-10-CM E46
ICD-10-CM code E46 represents Unspecified protein-calorie malnutrition. This is a billable/specific code in the Endocrine, Nutritional, and Metabolic chapter (block E46). The 2026 edition of ICD-10-CM E46 became effective on October 1, 2025.
Coding Tips for E46
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
E46 is a CMS-HCC v28 risk-adjustment code (category 21). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
E46 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under E46. Per CMS ICD-10-CM Tabular 2026.
- Malnutrition NOS
- Protein-calorie imbalance NOS
Type 1 Excludes
Pure excludes, these codes can never be coded together with E46. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- nutritional deficiency NOS (E63.9)
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Unspecified protein-calorie malnutrition. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for E46
Local Coverage Determinations (LCDs) from CMS MACs that list E46 as a covered diagnosis.
Showing top 10 of 325 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing E46.
2 Aetna
5 Medicare
Convert E46 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| E46 | 2638 | 10000 |
| E46 | 2639 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To E46
Other codes in section E40-E46 (Malnutrition).
ICD-10 E46, Billing FAQ
Is ICD-10 code E46 billable? +
Yes, E46 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to E46? +
ICD-10 E46 includes: Malnutrition NOS; Protein-calorie imbalance NOS.
What codes are Type 1 Excludes for E46? +
Type 1 Excludes (never code together with E46): nutritional deficiency NOS (E63.9)
Does E46 affect Medicare Advantage HCC risk adjustment? +
Yes. E46 maps to CMS-HCC v28 category 21. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is E46 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with E46? +
Procedures frequently paired with E46 include: J3420, J3425.
What ICD-9 codes does E46 map to? +
Per CMS GEMs, E46 maps to ICD-9 codes: 2638, 2639. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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