2026 ICD-10-CM Diagnosis Code I16.1Hypertensive emergency

ICD-10-CM Codes›I00–I99›I10-I1A›I16

ICD-10-CM I16.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I16.1 is a billable ICD-10-CM diagnosis code for hypertensive emergency. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 304 through 305. Coders also document this condition as hypertensive crisis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hypertension with complications and secondary hypertension.

Code Identity

ICD-10-CM Code
I16.1
Billable Status
Yes — Valid for Submission
Code Describes
Hypertensive emergency
Short Description
Hypertensive emergency
Same as the full description in the CMS dataset.
Parent Code
I16
Hypertensive crisis

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI10-I1AHypertensive diseases
CategoryI16Hypertensive crisis
This CodeI16.1Hypertensive emergency

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Hypertensive crisis
  • Hypertensive emergency

Tabular List NotesGuidance

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

Use Additional Code

  • code, if applicable, to identify specific organ dysfunction, such as:
  • acute kidney injury N17
  • acute myocardial infarction I21
  • acute pulmonary edema left and/or right ventricular failure J81.0 I50
  • aortic dissection I71.0
  • cerebral hemorrhage I60 I61 I62
  • cerebral infarction I63
  • eclampsia O15
  • hypertensive encephalopathy I67.4
  • seizure R56.9

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.

    • Hypertension, hypertensive(accelerated) (benign) (essential) (idiopathic) (malignant) (systemic)
      • emergency

Clinical ClassificationClinical

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

CCSR CIR008
Hypertension with complications and secondary hypertension
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Hypertensive Crisis

    a severe, acute increase in blood pressure that may result in stroke or myocardial ischemia.

Patient EducationClinical

High Blood Pressure

Blood pressure is the force of your blood pushing against the walls of your arteries. Each time your heart beats, it pumps blood into the arteries. Your blood pressure is highest when your heart beats, pumping the blood. This is called systolic pressure. When your heart is at rest, between beats, your blood pressure falls.

The full article covers:

  • What is blood pressure?
  • How is high blood pressure diagnosed?
  • What are the different types of high blood pressure?
  • Why do I need to worry about high blood pressure?
  • What are the treatments for high blood pressure?

Read the full article at MedlinePlus

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

Convert I16.1 to ICD-9-CMHistory

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

ICD-9-CM
401.9 Hypertension NOS
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement I16.1 replaces the following previously assigned code(s):

  • I10 - Essential (primary) hypertension
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I16.1Overview

Is I16.1 (Hypertensive crisis) a billable code?

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

What MS-DRG does I16.1 group to?

When hypertensive emergency is the principal diagnosis on an inpatient stay, it groups to MS-DRG 304, 305, with relative weights from 0.7551 to 1.1900 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of I16.1?

Under the General Equivalence Mappings, hypertensive emergency converts to ICD-9-CM 401.9 (hypertension NOS). The mapping is approximate, so confirm the match fits the documentation.

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.