What is ICD-10 code E16.9?

E16.9 is the ICD-10-CM diagnosis code for Disorder of pancreatic internal secretion, unspecified. A disorder of pancreatic hormone production or regulation, but the specific type is not identified. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E16.9 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E16.9 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. E16.9 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. E16.9 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for E16.9?

E16.9 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither community model rewards E16.9 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's V28/V24 community RAF score in either version. It does, however, map under the Part D RxHCC model (Pancreatic Disease and Disorders), which affects the ESRD and/or Part D (RxHCC) risk scores. Coders should check whether provider documentation supports a more specific child code that does map to a community payment HCC.

What should coders know when reporting E16.9?

This is an unspecified code; query the provider to identify the specific pancreatic endocrine disorder Use only when the specific disorder cannot be determined from available documentation

2026 ICD-10-CM E16.9: Disorder of pancreatic internal

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 lookupE16.9Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Other disorders of glucose regulation and pancreatic internal secretion (E15-E16)

E16.9

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

Disorder of pancreatic internal secretion, unspecified

A disorder of pancreatic hormone production or regulation, but the specific type is not identified.

Buddy Insight

E16.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

Mapped

HCC 66

Pancreatic Disease and Disorders

RAF 0.245

Code Book Path

Official

E16Other disorders of pancreatic internal secretion

E16.9Disorder of pancreatic internal secretion, unspecified

Inclusion Terms

Official

Islet-cell hyperplasia NOS
Pancreatic endocrine cell hyperplasia NOS

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E16.9 in this effective period.

Related Child Codes

Official

E16.0Drug-induced hypoglycemia without coma

E16.1Other hypoglycemia

E16.2Hypoglycemia, unspecified

E16.3Increased secretion of glucagon

E16.4Increased secretion of gastrin

Includes

Official

ICD-10-CM does not list Includes notes for E16.9 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for E16.9 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E16.9 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E16.9 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E16.9 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation should indicate suspected or confirmed pancreatic endocrine dysfunction.

Laboratory studies (insulin, glucagon, gastrin, or other pancreatic hormone levels) and clinical findings should be present.

The provider should be queried for additional specificity whenever possible.

MEAT Support

HCC Buddy guidance

Documentation should indicate suspected or confirmed pancreatic endocrine dysfunction.

Laboratory studies (insulin, glucagon, gastrin, or other pancreatic hormone levels) and clinical findings should be present.

The provider should be queried for additional specificity whenever possible.

Audit Caution

HCC Buddy guidance

This unspecified code should prompt a query for diagnostic specificity.

It should not be used long-term when a definitive diagnosis has been established.

Review laboratory results and specialist notes that may provide the specificity needed for a more precise code.

Common Mistakes

HCC Buddy guidance

E16.3 (increased glucagon) for glucagon excess

E16.4 (increased gastrin) for gastrin excess

E16.8 (other specified) when the disorder is identified but not glucagon or gastrin-related

K86.x (exocrine pancreatic disorders) for non-endocrine pancreatic conditions.

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 E16.9 an HCC code?

E16.9 is not in the CMS-HCC V28 or V24 community payment model, but it does map to Pancreatic Disease and Disorders under the Part D RxHCC model.

Code: E16.9
Description: Disorder of pancreatic internal secretion, unspecified
HCC (V28): No CMS-HCC V28 mapping
RAF: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

RxHCCHCC 66, Pancreatic Disease and Disorders

0.245

Each model's RAF is its CMS base weight for that model's standard population, so 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 segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work E16.9 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for E16.9

For E16.9 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

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

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed E16.9 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E16.9 is the ICD-10-CM diagnosis code for disorder of pancreatic internal secretion, unspecified. A disorder of pancreatic hormone production or regulation, but the specific type is not identified. E16.9 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering other disorders of glucose regulation and pancreatic internal secretion (e15-e16).

E16.9 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

This code does not map to a CMS-HCC V28 payment category. Capture depends on documentation that supports the diagnosis; verify the HCC assignment against the current CMS mapping for the applicable payment year. Coders reviewing E16.9 should check whether additional documentation would support a more specific child code in the same hierarchy that does map to a payment HCC, capturing the correct specificity is the highest-impact RAF improvement available within accurate coding.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E16.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is an unspecified code; query the provider to identify the specific pancreatic endocrine disorder
•Use only when the specific disorder cannot be determined from available documentation

Clinical Significance

E16.9 identifies unspecified disorder of pancreatic internal secretion. This nonspecific code indicates that a pancreatic endocrine dysfunction exists but has not been further characterized. It may be used during initial workup before a definitive diagnosis is established, but should be replaced with a more specific code once the condition is identified.

Documentation Requirements

✓Documentation should indicate suspected or confirmed pancreatic endocrine dysfunction.
✓Laboratory studies (insulin, glucagon, gastrin, or other pancreatic hormone levels) and clinical findings should be present.
✓The provider should be queried for additional specificity whenever possible.

Commonly Confused Codes

•E16.3 (increased glucagon) for glucagon excess
•E16.4 (increased gastrin) for gastrin excess
•E16.8 (other specified) when the disorder is identified but not glucagon or gastrin-related
•K86.x (exocrine pancreatic disorders) for non-endocrine pancreatic conditions.