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E34.00 ICD-10-CM Code: Carcinoid syndrome, unspecified

E34.00 maps to CMS-HCC V28 17. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

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HCC Buddy Code Card

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Code lookupE34.00

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Disorders of other endocrine glands (E20-E35)

E34.00

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

Carcinoid syndrome, unspecified

Carcinoid syndrome is a group of symptoms caused by hormone-secreting tumors, but the specific type or location is not specified.

Buddy the Bee presenting code insight

Buddy Insight

Carcinoid syndrome represents a paraneoplastic condition caused by vasoactive substances (serotonin, histamine, prostaglandins) secreted by neuroendocrine tumors, typically when hepatic metastases bypass first-pass metabolism.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 17

Coefficient HCC 17: 4.209 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 013

Code-level coefficient reference

ESRD/PACE

HCC 12

Code-level coefficient reference

RXHCC

HCC 22

Code-level coefficient reference

Code Book Path

Official
E34Other endocrine disordersE34.0Carcinoid syndromeE34.00Carcinoid syndrome, unspecified

Inclusion Terms

Official
  • Carcinoid disease, unspecified

Excludes 2

Official

No Excludes 2 notes are included in this display for E34.00. Check the code and parent instructions in the Code Book.

Related Codes

Official
E34.01Carcinoid heart syndromeE34.09Other carcinoid syndrome

Includes

Official

No Includes notes are included in this display for E34.00. 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, E20-E35, E34
  • galactorrhea (N64.3)Inherited from E00-E89, E20-E35, E34
  • gynecomastia (N62)Inherited from E00-E89, E20-E35, E34
  • pseudohypoparathyroidism (E20.1)Inherited from E00-E89, E20-E35, E34

Code First

Official

No Code First sequencing instructions are included in this display for E34.00. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for E34.00. Check the code and parent instructions in the Code Book.

Code Also

Official
  • the underlying disorder, such as:Inherited from E34.0
  • primary neuroendocrine tumors (C7A.-)Inherited from E34.0
  • secondary neuroendocrine tumors (C7B.-)Inherited from E34.0

Buddy Documentation Tip

HCC Buddy guidance
Documentation must confirm the presence of carcinoid syndrome with supporting evidence such as elevated 24-hour urine 5-hydroxyindoleacetic acid levels, chromogranin A levels, or imaging demonstrating neuroendocrine tumor.
The provider should specify which manifestations are present (flushing, diarrhea, bronchospasm, cardiac involvement) and the primary tumor site if known.
An echocardiogram should be documented to evaluate for carcinoid heart disease.

MEAT Support

HCC Buddy guidance
Documentation must confirm the presence of carcinoid syndrome with supporting evidence such as elevated 24-hour urine 5-hydroxyindoleacetic acid levels, chromogranin A levels, or imaging demonstrating neuroendocrine tumor.
The provider should specify which manifestations are present (flushing, diarrhea, bronchospasm, cardiac involvement) and the primary tumor site if known.
An echocardiogram should be documented to evaluate for carcinoid heart disease.

Audit Caution

HCC Buddy guidance
Always code the underlying neuroendocrine tumor separately with the appropriate C7A code.
Do not assign this code based solely on the presence of a carcinoid tumor without documented syndrome symptoms.
The unspecified code should prompt a query to determine if cardiac involvement is present, as E34.01 carries different clinical implications.
Ensure 5-hydroxyindoleacetic acid or other biomarker results support the diagnosis.

Common Mistakes

HCC Buddy guidance
E34.01 (Carcinoid heart syndrome) should be used when cardiac valve involvement is documented.
E34.09 (Other carcinoid syndrome) applies when specific non-cardiac manifestations are identified.
C-codes for neuroendocrine tumors (C7A.xxx) should be assigned for the underlying tumor.
Do not confuse with other causes of flushing such as menopause (N95.1) or rosacea (L71.x).

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 E34.00 an HCC code?

Yes. E34.00 (Carcinoid syndrome, unspecified) maps to HCC 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 4.209. 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: E34.00 is billable and maps to V28 HCC 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
E34.00
Description
Carcinoid syndrome, unspecified
HCC (V28)
HCC 17 — Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic
RAF reference coefficient
4.209
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic
4.209
ESRDHCC 12, Breast/Prostate/and Other Cancers and Tumors
Not separately weighted
RxHCCHCC 22, Prostate, Breast, Bladder, and Other Cancers and Tumors
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 E34.00 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E34.00

For E34.00, 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

E34.00 is the ICD-10-CM diagnosis code for carcinoid syndrome, unspecified. Carcinoid syndrome is a group of symptoms caused by hormone-secreting tumors, but the specific type or location is not specified. E34.00 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 CMS-HCC V28 risk adjustment model, E34.00 maps to Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic (HCC 17) with a source-labeled community, non-dual, aged reference coefficient of 4.209. No V24 mapping is shown for E34.00; 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.

This is an unspecified carcinoid code; look for documentation of the primary tumor site or specific carcinoid manifestations. For E34.00, 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 E34.00 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This is an unspecified carcinoid code; look for documentation of the primary tumor site or specific carcinoid manifestations
  • •If heart involvement is documented, use E34.01 instead; if other specific carcinoid syndromes are present, use E34.09

Clinical Significance

Carcinoid syndrome represents a paraneoplastic condition caused by vasoactive substances (serotonin, histamine, prostaglandins) secreted by neuroendocrine tumors, typically when hepatic metastases bypass first-pass metabolism. This unspecified code indicates the syndrome is present but the specific manifestation pattern has not been characterized, warranting further clinical evaluation to determine cardiac or other organ involvement.

Documentation Requirements

  • ✓Documentation must confirm the presence of carcinoid syndrome with supporting evidence such as elevated 24-hour urine 5-hydroxyindoleacetic acid levels, chromogranin A levels, or imaging demonstrating neuroendocrine tumor.
  • ✓The provider should specify which manifestations are present (flushing, diarrhea, bronchospasm, cardiac involvement) and the primary tumor site if known.
  • ✓An echocardiogram should be documented to evaluate for carcinoid heart disease.

Commonly Confused Codes

  • •E34.01 (Carcinoid heart syndrome) should be used when cardiac valve involvement is documented.
  • •E34.09 (Other carcinoid syndrome) applies when specific non-cardiac manifestations are identified.
  • •C-codes for neuroendocrine tumors (C7A.xxx) should be assigned for the underlying tumor.
  • •Do not confuse with other causes of flushing such as menopause (N95.1) or rosacea (L71.x).

Child Codes

E34.00Carcinoid syndrome, unspecified
HCC 17
E34.01Carcinoid heart syndrome
HCC 17
E34.09Other carcinoid syndrome
HCC 17

Code Hierarchy

└E34Other endocrine disorders└E34.0Carcinoid syndrome└E34.00Carcinoid syndrome, unspecified
└E34.00Carcinoid syndrome, unspecified

E34.00 code history

Code setChange
FY2025 (effective Oct 1, 2024)Added to the code set

Source: official CMS ICD-10-CM order and addenda files, FY2016 through FY2027.

Also searched as

  • E34 00
  • E3400

For E34.00, 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.

E34.00 maps to CMS-HCC V28 category 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for E34.00. 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 E34.00 in HCC Buddy

Open E34.00 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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