2027 ICD-10-CM Diagnosis Code E16.4Increased secretion of gastrin

ICD-10-CM Codes›E00–E89›E15-E16›E16

ICD-10-CM E16.4
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

E16.4 is a billable ICD-10-CM diagnosis code for increased secretion of gastrin. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 380 through 382. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified endocrine disorders.

E16.4 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 66 for payment year 2027.

Code Identity

ICD-10-CM Code
E16.4
Billable Status
Yes — Valid for Submission
Code Describes
Increased secretion of gastrin
Short Description
Increased secretion of gastrin
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 CodeE16.4Increased secretion of gastrin

Medicare Risk Adjustment (HCC)Billing

E16.4 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Part D (RxHCC)
RxHCC 66 — Pancreatic Disorders and Intestinal Malabsorption, Except Pancreatitis
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Abnormal hormone secretion
  • Abnormality of secretion of gastrin
  • Anastomotic ulcer due to Zollinger-Ellison syndrome
  • Cancerous ulcer
  • Drug-induced hypergastrinemia
  • Duodenal ulcer due to Zollinger-Ellison syndrome
  • Familial hypergastrinemic duodenal ulcer
  • Gastric ulcer due to Zollinger-Ellison syndrome
  • Gastrinoma
  • Hyperplasia of islet alpha cells with gastrin excess
  • Impaired acid inhibition of gastrin release
  • Increased gastrin secretion
  • Islet cell hyperplasia
  • Megaloblastic anemia due to Zollinger-Ellison syndrome
  • Zollinger-Ellison syndrome

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to E16.4: its own notes plus those printed at Chapter 4. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Hypergastrinemia
  • Hyperplasia of pancreatic endocrine cells with gastrin excess
  • Zollinger-Ellison syndrome

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases applies to 973 codes
  • transitory endocrine and metabolic disorders specific to newborn (P70-P74)

Notes

General instructions on how these codes are used.

From Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases applies to 973 codes
  • All neoplasms, whether functionally active or not, are classified in Chapter 2. Appropriate codes in this chapter (i.e. E05.8, E07.0, E16-E31, E34.-) may be used as additional codes to indicate either functional activity by neoplasms and ectopic endocrine tissue or hyperfunction and hypofunction of endocrine glands associated with neoplasms and other conditions classified elsewhere.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name E16.4, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming E16.4: they are not reported together with it, unless the two conditions are unrelated.

  • K29 Gastritis and duodenitis
    Zollinger-Ellison syndrome (E16.4)

Code First 1

These codes say to code first a condition named in the note, and E16.4 is one of the conditions named.

  • G63 Polyneuropathy in diseases classified elsewhere
    endocrine disease, except diabetes (E00-E07, E15-E16, E20-E34) names E15-E16, which includes this code

Notes 1

These notes mention E16.4.

  • Chapter 4 (E00-E89) Endocrine, nutritional and metabolic diseases
    All neoplasms, whether functionally active or not, are classified in Chapter 2. Appropriate codes in this chapter (i.e. E05.8, E07.0, E16-E31, E34.-) may be used as additional codes to indicate either functional activity by neoplasms and ectopic endocrine tissue or hyperfunction and hypofunction of endocrine glands associated with neoplasms and other conditions classified elsewhere. names E16-E31, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

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

Clinical InformationClinical

  • Zollinger-Ellison Syndrome

    a syndrome that is characterized by the triad of severe peptic ulcer, hypersecretion of gastric acid, and gastrin-producing tumors of the pancreas or other tissue (gastrinoma). this syndrome may be sporadic or be associated with multiple endocrine neoplasia type 1.

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 E16.4 to ICD-9-CMHistory

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

ICD-9-CM
251.5 Abnorm secretion gastrin
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 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About E16.4Overview

What is the ICD-10 code for increased secretion of gastrin?

The ICD-10-CM code for increased secretion of gastrin is E16.4 (sometimes written as E164). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is E16.4 (Other disorders of pancreatic internal secretion) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report increased secretion of gastrin on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does E16.4 group to?

When increased secretion of gastrin is the principal diagnosis on an inpatient stay, it groups to MS-DRG 381, 380, 382, with relative weights from 0.7283 to 1.9243 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of E16.4?

Under the General Equivalence Mappings, increased secretion of gastrin converts to ICD-9-CM 251.5 (abnorm secretion gastrin). The mapping is a direct match.

Does E16.4 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: E16.4 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 66 (Pancreatic Disorders and Intestinal Malabsorption, Except Pancreatitis).