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ICD-10 Code I27.23: Pulmonary hypertension due to lung diseases and hypoxia

I27.23 is a billable ICD-10 diagnosis code used to classify Pulmonary hypertension due to lung diseases and hypoxia 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).

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).

đź“‹Clinical overview

This ICD-10 code is commonly used when documentation describes pulmonary hypertension. The most accurate code depends on whether the condition is primary or secondary and whether the chart identifies a left-heart, lung-and-hypoxia, chronic-thromboembolic, or other driving mechanism.

When is it used?

  • May be used when a clinician documents pulmonary hypertension due to lung diseases and hypoxia 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.

đź©şClinical context

When commonly used
  • Cardiology, pulmonology, inpatient, and utilization-review workflows where pulmonary hypertension affects evaluation, treatment planning, or chronic disease follow-up.
  • Coding workflows where the chart identifies primary versus secondary pulmonary hypertension or names the underlying mechanism that changes final code specificity.
Common management context
  • Evaluation often includes echocardiography, cardiopulmonary assessment, imaging review, hemodynamic context, and follow-up of the underlying heart, lung, or thromboembolic condition.
  • Documentation usually becomes more specific when the chart identifies primary pulmonary hypertension, secondary pulmonary arterial hypertension, left-heart-disease association, lung-disease or hypoxia association, chronic thromboembolic disease, or another secondary pattern.
  • Specialist context already linked on this page includes Cardiologist, General Physician, Pulmonologist.

🔍Key distinctions

Important notes
  • This ICD-10 family captures pulmonary-hypertension diagnoses rather than systemic hypertension or unrelated pulmonary disorders without pulmonary-hypertension context.
  • Primary versus secondary disease and the documented underlying mechanism both affect final code specificity inside this family.
  • Cause detail matters here because left-heart-disease, lung-disease-and-hypoxia, and chronic-thromboembolic pulmonary hypertension are coded separately inside this family.
Related codes to consider
I27.20Pulmonary hypertension, unspecified
Related pulmonary-hypertension ICD-10 code; documentation often becomes more specific when the chart identifies primary versus secondary disease or names the heart, lung, hypoxia, or thromboembolic mechanism.
I27.21Secondary pulmonary arterial hypertension
Related pulmonary-hypertension ICD-10 code; documentation often becomes more specific when the chart identifies primary versus secondary disease or names the heart, lung, hypoxia, or thromboembolic mechanism.
I27.22Pulmonary hypertension due to left heart disease
Related pulmonary-hypertension ICD-10 code; documentation often becomes more specific when the chart identifies primary versus secondary disease or names the heart, lung, hypoxia, or thromboembolic mechanism.
I27.24Chronic thromboembolic pulmonary hypertension
Related pulmonary-hypertension ICD-10 code; documentation often becomes more specific when the chart identifies primary versus secondary disease or names the heart, lung, hypoxia, or thromboembolic mechanism.

Code hierarchy

chapter
9Diseases of the circulatory system (I00-I99)
block
I26-I28Pulmonary heart disease and diseases of pulmonary circulation
category
I27Other pulmonary heart diseases
category
I27.2Other secondary pulmonary hypertension
currentI27.2

Official coding notes

Inclusion terms
  • Group 3 pulmonary hypertension
Code also
  • associated lung disease, if known, such as:
  • bronchiectasis (J47.-)
  • cystic fibrosis with pulmonary manifestations (E84.0)
  • interstitial lung disease (J84.-)
  • pleural effusion (J90)
  • sleep apnea (G47.3-)

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 PhysicianPulmonologist

Coverage-related procedures and services

CPT 93350high
ECHOCARDIOGRAPHY, TRANSTHORACIC, REAL-TIME WITH IMAGE DOCUMENTATION (2D), INCLUDES M-MODE RECORDING, WHEN PERFORMED, DURING REST AND CARDIOVASCULAR STRESS TEST USING TREADMILL, BICYCLE EXERCISE AND/OR PHARMACOLOGICALLY INDUCED STRESS, WITH INTERPRETATION AND REPORT;
Source: CMS coverage guidance
CPT 93351high
ECHOCARDIOGRAPHY, TRANSTHORACIC, REAL-TIME WITH IMAGE DOCUMENTATION (2D), INCLUDES M-MODE RECORDING, WHEN PERFORMED, DURING REST AND CARDIOVASCULAR STRESS TEST USING TREADMILL, BICYCLE EXERCISE AND/OR PHARMACOLOGICALLY INDUCED STRESS, WITH INTERPRETATION AND REPORT; INCLUDING PERFORMANCE OF CONTINUOUS ELECTROCARDIOGRAPHIC MONITORING, WITH SUPERVISION BY A PHYSICIAN OR OTHER QUALIFIED HEALTH CARE PROFESSIONAL
Source: CMS coverage guidance
CPT 93352high
USE OF ECHOCARDIOGRAPHIC CONTRAST AGENT DURING STRESS ECHOCARDIOGRAPHY (LIST SEPARATELY IN ADDITION TO CODE FOR PRIMARY PROCEDURE)
Source: CMS coverage guidance
CPT 94621high
CARDIOPULMONARY EXERCISE TESTING, INCLUDING MEASUREMENTS OF MINUTE VENTILATION, CO2 PRODUCTION, O2 UPTAKE, AND ELECTROCARDIOGRAPHIC RECORDINGS
Source: CMS coverage guidance
CPT 93325high
DOPPLER ECHOCARDIOGRAPHY COLOR FLOW VELOCITY MAPPING (LIST SEPARATELY IN ADDITION TO CODES FOR ECHOCARDIOGRAPHY)
Source: CMS coverage guidance
CPT 93320high
DOPPLER ECHOCARDIOGRAPHY, PULSED WAVE AND/OR CONTINUOUS WAVE WITH SPECTRAL DISPLAY (LIST SEPARATELY IN ADDITION TO CODES FOR ECHOCARDIOGRAPHIC IMAGING); COMPLETE
Source: CMS coverage guidance

Coding guidelines

Common synonyms

Pulmonary hypertension due to lung diseases and hypoxia

Frequently asked questions

Code details

CodeI27.23
SystemICD10
Display namePulmonary hypertension due to lung diseases and hypoxia
ChapterDiseases of the circulatory system (I00-I99)
BlockPulmonary heart disease and diseases of pulmonary circulation

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

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