ICD-10 code E43 identifies unspecified severe protein-calorie malnutrition — a potentially life-threatening nutritional deficit where the provider has confirmed severity but has not documented a specific malnutrition subtype such as kwashiorkor or marasmus. This code is billable, valid for fiscal year 2026, and maps to MS-DRG 640 (with MCC) or 641 (without MCC) under ICD-10-CM Official Coding Guidelines Chapter 4. For revenue cycle teams, accurate use of E43 carries significant reimbursement and compliance implications — particularly in light of the Office of the Inspector General (OIG) findings that flagged approximately $1 billion in malnutrition-related overpayments for fiscal years 2016–2017.
What Does ICD-10 Code E43 Mean?
E43 — Unspecified severe protein-calorie malnutrition is used when a clinician has diagnosed and documented severe malnutrition but has not specified the precise form. It falls within the E40–E46 block, which encompasses the full spectrum of nutritional deficiency states.
Key attributes of this code:
- Billable/Valid: Yes — valid for encounters submitted on or after October 1, 2025
- Applicable setting: Inpatient and outpatient (with appropriate documentation)
- Applicable to: Starvation edema, severe emaciation, and semi-starvation presentations
- Gomez classification: Corresponds to body weight less than 60% of standard weight for age
- POA indicator required: Yes, for inpatient facility claims
What Conditions and Diagnoses Does E43 Cover?
E43 applies when documentation confirms the presence of severe protein-calorie deficiency without distinguishing between specific clinical syndromes. Terms that map directly to this code in the ICD-10-CM Alphabetic Index include:
- Starvation edema
- Severe malnourishment (unspecified type)
- Emaciation due to malnutrition
- Semi-starvation with severe caloric deficit
- Nutritional edema without predominant hypoproteinemia (when severity is classified as severe)
E43 may also apply when a clinician documents malnutrition as severe using recognized criteria — such as ASPEN (American Society for Parenteral and Enteral Nutrition) standards — but does not further specify the subtype.
What Does E43 Specifically Exclude?
Coders must apply the tabular Excludes1 and Excludes2 notes carefully. The following conditions are coded elsewhere and are not captured by E43:
- Kwashiorkor (E40) — protein-deficiency malnutrition with edema as the predominant feature
- Marasmus (E41) — severe malnutrition with predominant caloric deficit and no significant edema
- Marasmic kwashiorkor (E42) — severe malnutrition with features of both syndromes
- Moderate malnutrition (E44.0) — Gomez 60–74% of standard weight
- Mild malnutrition (E44.1) — Gomez 75–89% of standard weight
- Unspecified malnutrition (E46) — severity not documented by provider
When Is E43 the Right Code to Use?
In practice, selecting E43 correctly requires more than recognizing that a patient appears malnourished. The diagnosis-reporting hierarchy in ICD-10-CM instructs coders to code to the highest level of specificity supported by documentation. Use this decision sequence:
- Confirm the provider has used the word “severe” or documented criteria equivalent to severe (e.g., ASPEN acute-care criteria: <50% estimated energy requirement for >5 days, plus at least one physical finding of malnutrition).
- Confirm no specific subtype (kwashiorkor, marasmus, or marasmic kwashiorkor) has been documented by the physician or dietitian — if a type is specified, a more specific code takes priority.
- Confirm the diagnosis appears in the Assessment/Plan section of the provider’s note, not only in a dietitian’s note or nursing assessment (dietitian diagnoses may require physician co-sign per facility policy).
- Confirm a treatment plan is documented — the OIG expects to see that malnutrition influenced clinical management (e.g., TPN initiation, oral nutrition supplements, dietitian consult, extended length of stay).
- Verify consistency: documentation elsewhere in the record (history, nursing flowsheets, dietary notes) should not contradict the malnutrition diagnosis.
How Does E43 Differ From E41, E42, E44.0, and E46?
| Code | Description | Key Distinction | When to Use Instead of E43 |
|---|---|---|---|
| E40 | Kwashiorkor | Edema is the predominant feature; protein deficiency > caloric deficit | Provider documents kwashiorkor by name or edema-predominant presentation |
| E41 | Marasmus | Severe caloric deficit, profound wasting, no significant edema | Provider documents marasmus or calorie-predominant severe wasting |
| E42 | Marasmic kwashiorkor | Mixed features: severe wasting AND edema | Provider documents both presentations concurrently |
| E44.0 | Moderate protein-calorie malnutrition | Gomez 60–74% of standard weight; moderate severity only | Provider explicitly documents moderate severity |
| E44.1 | Mild protein-calorie malnutrition | Gomez 75–89% of standard weight; mild severity only | Provider documents mild severity |
| E46 | Unspecified malnutrition | Severity is not documented | No severity qualifier in provider documentation |
Coder insight: E46 is a frequent default — and a frequent audit finding. When documentation says only “malnutrition” without severity, query the provider before defaulting to E46. In many cases, clinical findings in the chart (labs, weight trends, dietitian assessments) support a query that yields a more specific and appropriately reimbursed code.
What Documentation Is Required to Support ICD-10 Code E43?
Documentation sufficiency is the single largest risk factor for E43 claims. The OIG’s 2020 malnutrition report found that many hospital claims lacked adequate clinical support for severe malnutrition diagnoses — making this one of the most audited nutritional codes in the inpatient setting.
What Must the Provider Document in the Clinical Notes?
- Explicit severity qualifier — the word “severe” or an equivalent ASPEN/GLIM criterion must appear in the physician’s or APP’s assessment note.
- Nutritional intake evidence — caloric and protein intake data, typically from dietitian assessments referencing the percentage of estimated needs met.
- Physical examination findings — at least one physical sign such as temporal wasting, bilateral orbital fat loss, decreased grip strength, or loss of subcutaneous fat.
- Diagnostic criteria methodology — reference to ASPEN or GLIM criteria used to establish severity is strongly preferred and increasingly expected by auditors.
- Treatment plan — documentation that the malnutrition diagnosis influenced management: dietary orders, TPN or enteral nutrition initiation, dietitian follow-up, or nutrition-related length-of-stay extension.
- Consistency across providers — physician, dietitian, and nursing notes should all be internally consistent; a physician note documenting malnutrition should not be preceded by a history section documenting “well-nourished.”
Which Diagnostic or Lab Results Support This Code?
No single lab value is required to code E43, but the following findings support the clinical picture and strengthen audit defensibility:
- Serum albumin (<3.0 g/dL) — note: current ASPEN criteria de-emphasize albumin due to its reflection of inflammation rather than nutritional status, but many payers still reference it
- Prealbumin (transthyretin) levels — more sensitive marker of acute nutritional status
- Significant weight loss (≥5% in 1 month or ≥10% in 6 months per ASPEN acute-care standards)
- BMI data — particularly BMI <18.5 in adults, though severity requires additional clinical criteria beyond BMI alone
- Grip strength measurement (hand dynamometry) — increasingly documented in functional nutrition assessments
- Dietary intake records from nursing or clinical nutrition
What Is the Documentation Standard for Inpatient vs. Outpatient Settings?
| Setting | Who Can Document the Diagnosis | Additional Requirements |
|---|---|---|
| Inpatient (acute care) | Attending physician or qualified APP | Must appear in Assessment/Plan; dietitian diagnosis typically requires physician query/co-sign; POA indicator required |
| Outpatient (clinic/office) | Treating provider | Diagnosis must be confirmed, not just suspected; dietitian notes alone are insufficient for code assignment |
| Long-term care (SNF/LTACH) | Attending physician; MDS assessment may capture nutritional data | Provider must document severity; MDS findings alone do not assign ICD-10 codes |
How Does E43 Affect Medical Billing and Claims?
E43 is one of the few nutritional diagnoses with direct DRG impact. When coded as a Major Complication or Comorbidity (MCC) in the inpatient setting, it drives assignment to MS-DRG 640, which carries a substantially higher relative weight — and therefore higher payment — than DRG 641 (without MCC). This reimbursement leverage is precisely why E43 has become a high-priority audit target.
Key billing considerations:
- MCC status: E43 qualifies as an MCC for inpatient DRG purposes — directly impacting base payment rates
- POA indicator: Required on all inpatient facility claims; “Y” (present on admission) must be supported by clinical documentation at the time of admission
- Medical necessity: Payers expect documentation demonstrating that malnutrition affected the treatment plan, not just that it was identified incidentally
- Observation vs. inpatient: E43 coded in outpatient observation does not carry DRG impact but may affect APR-DRG scoring in some state systems
What CPT or Procedure Codes Are Commonly Billed With E43?
| CPT Code | Description | Typical Pairing Context |
|---|---|---|
| 97802 | Medical nutrition therapy, initial assessment | Outpatient dietitian services for newly identified severe malnutrition |
| 97803 | Medical nutrition therapy, re-assessment | Follow-up nutrition counseling for established E43 patients |
| 43760 | Nasogastric tube insertion | Enteral feeding initiation for severe malnutrition |
| 36568 / 36569 | PICC line insertion | Parenteral nutrition (TPN) access for severe cases |
| 99213–99215 | Office/outpatient E&M | Ongoing management of malnutrition in outpatient settings |
Are There Any Prior Authorization or Coverage Restrictions?
- Medicare: No LCD exists exclusively for malnutrition coding, but medical necessity review criteria apply; documentation must demonstrate clinical impact on care
- Medicaid: Varies by state; some state Medicaid programs apply enhanced review to malnutrition MCCs on inpatient claims
- Commercial payers: Many conduct post-payment DRG validation audits specifically targeting MCC/CC designations including E43; clinical documentation improvement (CDI) programs should address this code proactively
- Enteral/parenteral nutrition: TPN and enteral formula coverage (HCPCS B-codes) requires separate medical necessity documentation beyond the malnutrition diagnosis alone
What Coding Errors Should You Avoid With E43?
Malnutrition coding has been an OIG audit target since at least 2018. The following errors are most frequently cited in recovery audit contractor (RAC) and MAC reviews:
- Coding E43 from dietitian documentation alone — dietitians are not credentialed to establish diagnoses for coding purposes in most settings; a physician must document or co-sign the diagnosis.
- Defaulting to E43 when E41, E40, or E42 is supported — coders should query the provider when documentation describes specific presentation features (edema, severe wasting) rather than defaulting to “unspecified.”
- Coding E43 without documented severity criteria — if the provider writes “malnutrition” without a severity qualifier, E46 is technically correct; querying for severity is appropriate.
- Omitting the POA indicator — or assigning “N” (not present on admission) without clinical support; malnutrition is commonly present on admission and must be appropriately flagged.
- Inconsistent documentation — coding E43 when earlier chart entries document “well-nourished” without reconciling the contradiction.
- Failing to capture treatment plan linkage — documentation that a malnutrition diagnosis did not affect treatment will draw auditor scrutiny.
What Do Auditors Look for When Reviewing Claims With E43?
- Physician documentation of severity in the Assessment/Plan (not just problem list)
- Evidence that malnutrition was treated or affected clinical decision-making
- Consistency of the malnutrition diagnosis across all clinical disciplines
- POA indicator accuracy — was malnutrition present at the time of admission?
- Whether documentation of ASPEN or GLIM criteria appears (or any recognized diagnostic methodology)
- Whether length-of-stay was extended or treatment was modified due to the nutritional diagnosis
- Absence of contradicting “well-nourished” notations in earlier documentation
How Does E43 Relate to Other ICD-10 Codes?
E43 exists within a precise hierarchy of malnutrition codes. Coders and CDI specialists should understand both the lateral relationships (other severity levels) and the hierarchical relationships (sequencing rules when E43 appears with comorbidities).
| Code | Relationship to E43 | Key Distinction |
|---|---|---|
| E40 | Excludes1 (cannot be coded with E43) | Kwashiorkor — protein-deficiency predominant |
| E41 | Excludes1 (cannot be coded with E43) | Marasmus — calorie-deficiency predominant |
| E42 | Excludes1 (cannot be coded with E43) | Combined severe malnutrition |
| E44.0 | Alternative (moderate severity) | Lower severity tier; different DRG impact |
| E46 | Alternative (unspecified severity) | Used only when severity is not documented |
| E64.0 | Sequela code | Late effects of protein-calorie malnutrition — coded when residual effects remain after active disease resolved |
| Z87.39 | Personal history | History of nutritional deficiency when no longer active |
What Is the Correct Code Sequencing When E43 Appears With Other Diagnoses?
- Principal diagnosis: In inpatient settings, sequence the condition established after study to be chiefly responsible for admission. E43 may be principal if malnutrition was the primary reason for admission (e.g., patient admitted specifically for TPN initiation).
- Secondary diagnosis: More commonly, E43 is sequenced as a secondary MCC alongside a principal diagnosis such as sepsis, cancer, or chronic organ failure.
- Underlying condition: When malnutrition is directly attributable to a specific disease (e.g., Crohn’s disease, head and neck cancer), the underlying condition should be coded first where guideline instruction requires it; however, no ICD-10-CM “code first” instruction appears directly under E43.
- Use additional code: Coders should assign additional codes for associated conditions such as hypoalbuminemia (E77.1 is not applicable; use documented electrolyte or protein disorders as appropriate), dysphagia (R13.1x), or pressure injuries (L89.xx) that co-exist with and are clinically related to severe malnutrition.
Real-World Coding Scenario — How E43 Is Applied in Practice
Patient encounter: A 74-year-old male admitted for community-acquired pneumonia. The admitting physician’s history and physical documents “patient appears cachectic.” On day two, the registered dietitian assesses the patient and documents: “Severe protein-calorie malnutrition per ASPEN criteria — caloric intake <50% estimated needs for >7 days, bilateral temporal wasting, grip strength in <10th percentile, 12% weight loss over 3 months.” No physician note references malnutrition on admission. On day four, following a CDI query, the attending documents in the progress note: “Patient has severe malnutrition per ASPEN criteria; TPN initiated; nutritional consult ongoing.”
Correct Code Application
- Principal diagnosis: J18.9 (Pneumonia, unspecified organism)
- Secondary diagnosis: E43 (Unspecified severe protein-calorie malnutrition) — coded as MCC
- POA indicator for E43: “Y” — clinical findings (weight loss, wasting) were present on admission even though physician documentation was not formalized until day four; CDI query appropriately clarified
- Rationale: Physician-documented severity after query, treatment plan modified (TPN initiated), ASPEN criteria referenced
Common Mistake in This Scenario
- Incorrect approach: Coding E43 directly from the dietitian’s day-two note without waiting for physician query or co-sign
- Why it fails: Under ICD-10-CM Official Coding Guidelines Section I.B.5, diagnoses documented by non-physician providers (including dietitians) are not coded unless a credentialed treating provider confirms the diagnosis; coding from dietitian note alone is a codeable error and a primary RAC audit finding
- Additional error: Assigning POA indicator “N” because the physician note appeared on day four — the clinical findings were clearly present on admission, making “Y” correct once physician documentation was obtained
Frequently Asked Questions About ICD-10 Code E43
Is ICD-10 Code E43 Valid for Use in 2026?
ICD-10 code E43 is a valid, billable diagnosis code for fiscal year 2026 with no changes to its description or validity status. Coders should verify annually against the CMS ICD-10-CM Official Coding Guidelines release each October to confirm no revisions have been applied to the E40–E46 malnutrition block.
What Is the Difference Between E43 and E46?
E43 designates severe protein-calorie malnutrition, while E46 is used when malnutrition is documented without any severity qualifier. E46 does not qualify as an MCC and carries a substantially lower DRG impact; when clinical documentation supports querying for severity, coders and CDI specialists should do so before defaulting to E46.
Can a Dietitian’s Note Alone Support E43 Coding?
A dietitian’s note alone is generally insufficient to support E43 coding in most settings. The ICD-10-CM Official Coding Guidelines restrict code assignment based on provider documentation from credentialed treating providers (physicians, APPs); dietitian diagnoses require physician acknowledgment or co-signature to be codeable. This is consistently one of the most cited errors in malnutrition RAC audits.
What ASPEN Criteria Must Be Met to Code E43 in an Acute Care Setting?
Per ASPEN guidance, severe malnutrition in acute illness requires: caloric intake below 50% of estimated needs for more than five days, plus at least two of the following — significant weight loss, loss of subcutaneous fat, loss of muscle mass, localized or generalized fluid accumulation, or diminished grip strength. All criteria and clinical findings should appear in the provider’s documentation to support E43 in the inpatient setting.
Does E43 Always Function as an MCC for Inpatient DRG Assignment?
E43 qualifies as a Major Complication or Comorbidity (MCC) under the MS-DRG system when coded as a secondary diagnosis alongside an appropriate principal diagnosis. Its MCC status is one reason it is a high-priority audit target; payers scrutinize whether documentation adequately supports both the diagnosis and its severity level before allowing the higher-weighted DRG to stand.
What Should I Do If Only “Malnutrition” Is Documented Without a Severity Qualifier?
When documentation states only “malnutrition” without severity, the correct code is E46 — unspecified malnutrition. Coders should initiate a physician query to determine whether the clinical findings in the chart support a severity designation (moderate or severe). Querying is appropriate and encouraged; coders should never assume or infer severity from lab values or dietitian notes alone.
What Is the ICD-10 Sequela Code for Resolved Protein-Calorie Malnutrition?
When a patient has residual effects from prior severe malnutrition — such as developmental delays, growth deficiencies, or neurological sequelae — but the active malnutrition itself is no longer present, code E64.0 (Sequelae of protein-calorie malnutrition) is used. E43 would not be appropriate in this context because the active condition has resolved.
Key Takeaways
- E43 is for confirmed, provider-documented severe malnutrition where the specific subtype (kwashiorkor, marasmus) is not identified; if a subtype is documented, code to E40, E41, or E42 instead.
- Dietitian documentation alone does not support code assignment — a physician or qualified APP must document or co-sign the diagnosis for coding purposes.
- ASPEN or GLIM criteria documentation significantly strengthens audit defensibility — encourage providers to explicitly reference the diagnostic methodology used.
- E43 qualifies as an MCC in the MS-DRG system, making it a high-audit-priority code; robust clinical documentation is essential to withstand RAC and MAC review.
- POA indicator accuracy matters — malnutrition findings present on admission (weight loss, wasting, inadequate intake) should support a “Y” POA even if physician documentation was formalized later after a CDI query.
- Coding E43 from an undifferentiated “malnutrition” note is a compliance risk — E46 is the appropriate fallback, and a provider query is the appropriate next step.
- For ongoing coding audit preparation and revenue cycle compliance in malnutrition coding, consult the AHA Coding Clinic for any published guidance on nutritional code queries and the annual CMS ICD-10-CM Official Coding Guidelines update.
Sources referenced: CMS ICD-10-CM Official Coding Guidelines FY2026; ACDIS/HCPro Malnutrition Coding Q&A; ASPEN Malnutrition Consensus Statement; OIG Report OEI-02-18-00100 (July 2020) — Hospitals Incorrectly Billed Medicare for Severe Malnutrition.