ICD10BillableValid for clinical use

ICD-10 Code I1A.0: Resistant hypertension

I1A.0 is a billable ICD-10 diagnosis code used to classify Resistant hypertension in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the circulatory system (I00-I99).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the circulatory system (I00-I99).

When is it used?

  • May be used when a clinician documents resistant hypertension in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
9Diseases of the circulatory system (I00-I99)
block
I10-I1AHypertensive diseases
category
I1AOther hypertension
currentI1A

Official coding notes

Inclusion terms
  • Apparent treatment resistant hypertension
  • Treatment resistant hypertension
  • True resistant hypertension
Applicable to
  • specific type of existing hypertension, if known, such as:
  • essential hypertension (I10)
  • secondary hypertension (I15.-)
Code first
  • specific type of existing hypertension, if known, such as:
  • essential hypertension (I10)
  • secondary hypertension (I15.-)

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

CardiologistGeneral Physician

Coverage-related procedures and services

CPT 43845high
GASTRIC RESTRICTIVE PROCEDURE WITH PARTIAL GASTRECTOMY, PYLORUS-PRESERVING DUODENOILEOSTOMY AND ILEOILEOSTOMY (50 TO 100 CM COMMON CHANNEL) TO LIMIT ABSORPTION (BILIOPANCREATIC DIVERSION WITH DUODENAL SWITCH)
Source: CMS coverage guidance
CPT 43846high
GASTRIC RESTRICTIVE PROCEDURE, WITH GASTRIC BYPASS FOR MORBID OBESITY; WITH SHORT LIMB (150 CM OR LESS) ROUX-EN-Y GASTROENTEROSTOMY
Source: CMS coverage guidance
CPT 43847high
GASTRIC RESTRICTIVE PROCEDURE, WITH GASTRIC BYPASS FOR MORBID OBESITY; WITH SMALL INTESTINE RECONSTRUCTION TO LIMIT ABSORPTION
Source: CMS coverage guidance
CPT 43770high
LAPAROSCOPY, SURGICAL, GASTRIC RESTRICTIVE PROCEDURE; PLACEMENT OF ADJUSTABLE GASTRIC RESTRICTIVE DEVICE (EG, GASTRIC BAND AND SUBCUTANEOUS PORT COMPONENTS)
Source: CMS coverage guidance
CPT 43644high
LAPAROSCOPY, SURGICAL, GASTRIC RESTRICTIVE PROCEDURE; WITH GASTRIC BYPASS AND ROUX-EN-Y GASTROENTEROSTOMY (ROUX LIMB 150 CM OR LESS)
Source: CMS coverage guidance
CPT 43645high
LAPAROSCOPY, SURGICAL, GASTRIC RESTRICTIVE PROCEDURE; WITH GASTRIC BYPASS AND SMALL INTESTINE RECONSTRUCTION TO LIMIT ABSORPTION
Source: CMS coverage guidance

Coding guidelines

Common synonyms

Resistant hypertension

Frequently asked questions

Code details

CodeI1A.0
SystemICD10
Display nameResistant hypertension
ChapterDiseases of the circulatory system (I00-I99)
BlockHypertensive diseases

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Hypertension, hypertensive(accelerated) (benign) (essential) (idiopathic) (malignant) (systemic)

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code I1A.0 for Resistant hypertension | HealthAssure