2026 ICD-10-CM Diagnosis Code E16.1Other hypoglycemia

ICD-10-CM Codes›E00–E89›E15-E16›E16

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

E16.1 is a billable ICD-10-CM diagnosis code for other hypoglycemia. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified endocrine disorders.

Code Identity

ICD-10-CM Code
E16.1
Billable Status
Yes — Valid for Submission
Code Describes
Other hypoglycemia
Short Description
Other hypoglycemia
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 CodeE16.1Other hypoglycemia

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Alimentary hyperinsulinemia
  • Alimentary hypoglycemia
  • Autoimmune hypoglycemia
  • Autosomal dominant hyperinsulinism due to Kir6.2 deficiency
  • Autosomal dominant hyperinsulinism due to SUR1 deficiency
  • Autosomal recessive hyperinsulinism due to Kir6.2 deficiency
  • Autosomal recessive hyperinsulinism due to SUR1 deficiency
  • Diazoxide-resistant diffuse hyperinsulinism
  • Diazoxide-resistant focal hyperinsulinism
  • Diazoxide-resistant focal hyperinsulinism due to Kir6.2 deficiency
  • Diazoxide-resistant focal hyperinsulinism due to SUR1 deficiency
  • Diazoxide-resistant hyperinsulinism
  • Diazoxide-sensitive diffuse hyperinsulinism
  • Ectopic hyperinsulinism
  • Ectopic IGF hypoglycemia
  • Ectopic IGF-1 hypoglycemia
  • Ectopic IGF-2 hypoglycemia
  • Exercise-induced hyperinsulinism
  • Familial hyperinsulinemic hypoglycemia
  • Fasting hypoglycemia
  • Functional hyperinsulinism
  • Hyperammonemia
  • Hyperglycemia due to diabetes mellitus
  • Hyperinsulinemia due to malignant insulinoma
  • Hyperinsulinism
  • Hyperinsulinism and hyperammonemia syndrome
  • Hyperinsulinism due to deficiency of glucokinase
  • Hyperinsulinism due to focal adenomatous hyperplasia
  • Hyperinsulinism due to HNF1A deficiency
  • Hyperinsulinism due to HNF4A deficiency
  • Hyperinsulinism due to insulin receptor deficiency
  • Hyperinsulinism due to short chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency
  • Hyperinsulinism due to uncoupling protein 2 deficiency
  • Hyperplasia of pancreatic islet beta cell
  • Hypoglycemia
  • Hypoglycemia due to neoplasm
  • Hypoglycemia of childhood
  • Iatrogenic hyperinsulinism
  • Idiopathic postprandial hypoglycemia
  • Impaired glucose tolerance with hyperinsulism
  • Islet cell hyperplasia
  • Ketotic hypoglycemia
  • Metabolic complication of procedures
  • Mixed hypoglycemia
  • Neuroglycopenia
  • Non-diabetic disorder of endocrine pancreas
  • Non-diabetic hypoglycemia
  • Post gastrointestinal tract surgery hypoglycemia
  • Post-prandial hypoglycemia
  • Reactive hypoglycemia
  • Recurrent severe hypoglycemia
  • Somogyi phenomenon

Tabular List NotesGuidance

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

Inclusion Terms

  • Functional hyperinsulinism
  • Functional nonhyperinsulinemic hypoglycemia
  • Hyperinsulinism NOS
  • Hyperplasia of pancreatic islet beta cells NOS

Use Additional Code

  • code for hypoglycemia level, if applicable E16.A

Type 1 Excludes

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.

    • Encephalopathy(acute)
      • in (due to) (with)
        • hyperinsulinism
    • Encephalopathy(acute)
      • posthypoglycemic (coma)
    • Hyperinsulinism(functional)
    • Hyperinsulinism(functional)
      • with
        • encephalopathy
    • Hyperinsulinism(functional)
      • ectopic
    • Hyperplasia, hyperplastic
      • pancreatic islet cells
        • beta
    • Hypoglycemia(spontaneous)
      • functional, nonhyperinsulinemic
    • Hypoglycemia(spontaneous)
      • infantile
    • Hypoglycemia(spontaneous)
      • reactive (not drug-induced)

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

  • Congenital Hyperinsulinism

    a familial, nontransient hypoglycemia with defects in negative feedback of glucose-regulated insulin release. clinical phenotypes include hypoglycemia; hyperinsulinemia; seizures; coma; and often large birth weight. several sub-types exist with the most common, type 1, associated with mutations on an atp-binding cassette transporters (subfamily c, member 8).

  • Hypoglycemia

    a syndrome of abnormally low blood glucose level. clinical hypoglycemia has diverse etiologies. severe hypoglycemia eventually lead to glucose deprivation of the central nervous system resulting in hunger; sweating; paresthesia; impaired mental function; seizures; coma; and even death.

  • Hyperinsulinism

    a syndrome with excessively high insulin levels in the blood. it may cause hypoglycemia. etiology of hyperinsulinism varies, including hypersecretion of a beta cell tumor (insulinoma); autoantibodies against insulin (insulin antibodies); defective insulin receptor (insulin resistance); or overuse of exogenous insulin or hypoglycemic agents.

  • Nesidioblastosis

    an inherited autosomal recessive syndrome characterized by the disorganized formation of new islets in the pancreas and congenital hyperinsulinism. it is due to focal hyperplasia of pancreatic islet cells budding off from the ductal structures and forming new islets of langerhans. mutations in the islet cells involve the potassium channel gene kcnj11 or the atp-binding cassette transporter gene abcc8, both on chromosome 11.

  • Carbamoyl-Phosphate Synthase I Deficiency Disease

    a urea cycle disorder manifesting in infancy as lethargy, emesis, seizures, alterations of muscle tone, abnormal eye movements, and an elevation of serum ammonia. the disorder is caused by a reduction in the activity of hepatic mitochondrial carbamoyl-phosphate synthase (ammonia). (menkes, textbook of child neurology, 5th ed, pp50-1)

  • Hyperammonemia

    elevated level of ammonia in the blood. it is a sign of defective catabolism of amino acids or ammonia to urea.

  • Hyperlysinemias

    a group of inherited metabolic disorders which have in common elevations of serum lysine levels. enzyme deficiencies of alpha-aminoadipic semialdehyde dehydrogenase and the saccharopine dehydrogenases have been associated with hyperlysinemia. clinical manifestations include mental retardation, recurrent emesis, hypotonia, lethargy, diarrhea, and developmental delay. (from menkes, textbook of child neurology, 5th ed, p56)

  • Rett Syndrome

    an inherited neurological developmental disorder that is associated with x-linked inheritance and may be lethal in utero to hemizygous males. the affected female is normal until the age of 6-25 months when progressive loss of voluntary control of hand movements and communication skills; ataxia; seizures; autistic behavior; intermittent hyperventilation; and hyperammonemia appear. (from menkes, textbook of child neurology, 5th ed, p199)

  • Idiopathic Ketotic Hypoglycemia|Accelerated Starvation

    ketotic hypoglycemia that usually occurs in young, thin children in association with infection or fasting, and which typically resolves by age 6-8 years.

  • Ketotic Hypoglycemia

    a condition in which hypoglycemia is accompanied by ketosis. this condition may be a manifestation of another condition such as glycogen storage disease, ketone utilization defects, growth hormone deficiency, or cortisol deficiency.

Patient EducationClinical

Hypoglycemia

Blood glucose, or blood sugar, is the main sugar found in your blood. It is your body's primary source of energy. It comes from the food you eat. Your body breaks down most of that food into glucose and releases it into your bloodstream. When your blood glucose goes up, it signals your pancreas to release insulin.

The full article covers:

  • What is blood glucose?
  • What is hypoglycemia?
  • What causes hypoglycemia?
  • What are the symptoms of hypoglycemia?
  • How is hypoglycemia diagnosed?
  • What are the treatments for hypoglycemia?
  • Can hypoglycemia be prevented?

Read the full article at MedlinePlus

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

Convert E16.1 to ICD-9-CMHistory

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

ICD-9-CM
251.1 Oth spcf hypoglycemia
Approximate The match is approximate rather than exact.

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 E16.1Overview

Is E16.1 (Other disorders of pancreatic internal secretion) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report other hypoglycemia on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does E16.1 group to?

When other hypoglycemia 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 E16.1?

Under the General Equivalence Mappings, other hypoglycemia converts to ICD-9-CM 251.1 (oth spcf hypoglycemia). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.