2026 ICD-10-CM Diagnosis Code E16.9Disorder of pancreatic internal secretion, unspecified

ICD-10-CM Codes›E00–E89›E15-E16›E16

ICD-10-CM E16.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E16.9 is a billable ICD-10-CM diagnosis code for disorder of pancreatic internal secretion, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 643 through 645. Coders also document this condition as abnormal hormone secretion. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified endocrine disorders.

Code Identity

ICD-10-CM Code
E16.9
Billable Status
Yes — Valid for Submission
Code Describes
Disorder of pancreatic internal secretion, unspecified
Short Description
Disorder of pancreatic internal secretion, unspecified
Same as the full description in the CMS dataset.
Parent Code
E16
Other disorders of pancreatic internal secretion

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE15-E16Other disorders of glucose regulation and pancreatic internal secretion
CategoryE16Other disorders of pancreatic internal secretion
This CodeE16.9Disorder of pancreatic internal secretion, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal hormone secretion
  • Abnormal pancreatic secretion
  • Abnormality of secretion of gastrin
  • Decreased pancreatic secretion
  • Disorder of endocrine pancreas
  • Disorder of pancreatic internal secretion
  • Hyperinsulinism due to focal adenomatous hyperplasia
  • Increased pancreatic secretion
  • Islet cell hyperplasia

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Islet-cell hyperplasia NOS
  • Pancreatic endocrine cell hyperplasia NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disorder(of)
      • pancreatic internal secretion
    • Hyperplasia, hyperplastic
      • pancreatic islet cells
    • Increase, increased
      • secretion
        • pancreas, endocrine

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR END015
Other specified and unspecified endocrine disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Pancreatic Diseases

The pancreas is a gland behind your stomach and in front of your spine. It produces juices that help break down food and hormones that help control blood sugar levels. Problems with the pancreas can lead to many health problems. These include:

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert E16.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
251.9 Pancreatic disorder NOS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About E16.9Overview

Is E16.9 (Other disorders of pancreatic internal secretion) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report disorder of pancreatic internal secretion, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does E16.9 group to?

When disorder of pancreatic internal secretion, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 643, 644, 645, with relative weights from 0.7683 to 1.6461 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of E16.9?

Under the General Equivalence Mappings, disorder of pancreatic internal secretion, unspecified converts to ICD-9-CM 251.9 (pancreatic disorder NOS). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.