2027 ICD-10-CM Diagnosis Code I16.9Hypertensive crisis, unspecified

ICD-10-CM Codes›I00–I99›I10-I1A›I16

ICD-10-CM I16.9
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

I16.9 is a billable ICD-10-CM diagnosis code for hypertensive crisis, unspecified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 304 through 305. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 1 closely related codes. 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.

I16.9 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 187 for payment year 2027.

Code Identity

ICD-10-CM Code
I16.9
Billable Status
Yes — Valid for Submission
Code Describes
Hypertensive crisis, unspecified
Short Description
Hypertensive crisis, unspecified
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 CodeI16.9Hypertensive crisis, unspecified

Medicare Risk Adjustment (HCC)Billing

I16.9 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 187 — Hypertension
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.

  • Hypertensive crisis

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to I16.9: its own notes plus those printed at I16, block I10-I1A, and Chapter 9. A note printed at a category, block or chapter applies to every code under it.

Excludes1

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

From Block I10-I1A Hypertensive diseases applies to 18 codes
  • neonatal hypertension (P29.2)
  • primary pulmonary hypertension (I27.0)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block I10-I1A Hypertensive diseases applies to 18 codes
  • hypertensive disease complicating pregnancy, childbirth and the puerperium (O10-O11, O13-O16)
From Chapter 9 (I00-I99) Diseases of the circulatory system applies to 1,433 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • transient cerebral ischemic attacks and related syndromes (G45.-)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Block I10-I1A Hypertensive diseases applies to 18 codes
  • code to identify:
  • exposure to environmental tobacco smoke (Z77.22)
  • history of tobacco dependence (Z87.891)
  • occupational exposure to environmental tobacco smoke (Z57.31)
  • tobacco dependence (F17.-)
  • tobacco use (Z72.0)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From I16 Hypertensive crisis applies to 3 codes
  • any identified hypertensive disease (I10-I15, I1A)

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

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name I16.9, its category, or a range that includes it.

Use Additional Code 3

These codes say to use an additional code from the note, and I16.9 is one of the codes named.

  • G90.81 Serotonin syndrome
    hypertensive crisis (I16.-) names I16.-, which includes this code
  • G31.84 Mild cognitive impairment of uncertain or unknown etiology
    hypertension (I10-I1A) names I10-I1A, which includes this code
  • Block I60-I69 Cerebrovascular diseases
    hypertension (I10-I1A) names I10-I1A, which includes this code

Code Also 2

These codes say I16.9 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • Block I20-I25 Ischemic heart diseases
    the presence of hypertension (I10-I1A) names I10-I1A, which includes this code
  • Z15.3 Genetic susceptibility to kidney disease
    if applicable, hypertension (I10-I1A) names I10-I1A, 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 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 I16.9 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 I16.9 replaces the following previously assigned code(s):

  • I10 - Essential (primary) hypertension
FY 2019AddedAdded to the ICD-10-CM code setEffective October 1, 2018.
FY 2020–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About I16.9Overview

What is the ICD-10 code for hypertensive crisis, unspecified?

The ICD-10-CM code for hypertensive crisis, unspecified is I16.9 (sometimes written as I169). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is I16.9 (Hypertensive crisis) a billable code?

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

What MS-DRG does I16.9 group to?

When hypertensive crisis, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 305, 304, with relative weights from 0.7579 to 1.2010 depending on complications. Higher weights mean higher Medicare reimbursement.

Is I16.9 a CC or MCC?

CMS lists I16.9 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 1 closely related codes in its exclusion list.

Can I16.9 be reported with P29.2?

Not as a rule. The Excludes1 note at block I10-I1A, which applies to I16.9, lists "neonatal hypertension (P29.2)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

Does I16.9 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: I16.9 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 187 (Hypertension).