ICD-10 Coding and Documentation for Asthma

by | Last updated Jun 30, 2023 | Published on Feb 26, 2015 | Resources, Articles | 0 comments

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With the ICD-10 implementation date drawing near, it is very important to have a thorough understanding of ICD-10 coding and documentation for asthma as it is a chronic condition common among the general population. Two axes of classification rarely documented by physicians in ICD-9 are not there in the ICD-10 system. Instead, two new axes of classification have been added in this coding system. If healthcare providers prepare ahead for ICD-10 documentation, they can avoid sudden drop in revenue at the time of implementation of the new coding system. Before going to ICD-10 coding in detail, let’s take a look at the prevailing ICD-9 codes for asthma.

ICD-9 codes  

  • 493: Asthma
  • 493.0: Extrinsic asthma
  • 493.00: Extrinsic asthma, unspecified
  • 493.01: Extrinsic asthma with status asthmaticus
  • 493.02: Extrinsic asthma with (acute) exacerbation
  • 493.1: Intrinsic asthma
  • 493.10: Intrinsic asthma, unspecified
  • 493.11: Intrinsic asthma with status asthmaticus
  • 493.12: Intrinsic asthma with (acute) exacerbation
  • 493.2: Chronic obstructive asthma
  • 493.20: Chronic obstructive asthma, unspecified
  • 493.21: Chronic obstructive asthma with status asthmaticus
  • 493.22: Chronic obstructive asthma with (acute) exacerbation
  • 493.8: Other forms of asthma
  • 493. 81: Exercise induced bronchospasm
  • 493.82: Cough variant asthma
  • 493.9: Asthma unspecified
  • 493.90: Asthma, unspecified type, unspecified
  • 493.91: Asthma, unspecified type, with status asthmaticus
  • 493.92: Asthma, unspecified type, with (acute) exacerbation

ICD-10 Coding

The new system does not compel physicians to categorize asthma as either intrinsic or extrinsic. There are no separate codes for chronic obstructive asthma as well. Instead, asthma is just asthma and categorized by its degree of severity. The terms mild, moderate and severe are used in the codes to differentiate the severity levels. The condition is further categorized as either intermittent or persistent. The subcategories are broken down by complication – uncomplicated, with acute exacerbation and with status asthma. In addition to this, there are codes for other and unspecified asthma. The ICD-10 codes for asthma are given below.

  • J45: Asthma
  • J45.2: Mild intermittent asthma
  • J45.20: Mild intermittent asthma, uncomplicated
  • J45.21: Mild intermittent asthma, with (acute) exacerbation
  • J45.22: Mild intermittent asthma, with status asthmaticus
  • J45.3: Mild persistent asthma
  • J45.30: Mild persistent asthma, uncomplicated
  • J45.31: Mild persistent asthma, with (acute) exacerbation
  • J45.32: Mild persistent asthma, with status asthmaticus
  • J45.4: Moderate persistent asthma
  • J45.40: Moderate persistent asthma, uncomplicated
  • J45.41: Moderate persistent asthma, with (acute) exacerbation
  • J45.42: Moderate persistent asthma, with status asthmaticus
  • J45.5: Severe persistent asthma
  • J45.50: Severe persistent asthma, uncomplicated
  • J45.51: Severe persistent asthma, with (acute) exacerbation
  • J45.52: Severe persistent asthma, with status asthmaticus
  • J45.9: Other and unspecified asthma
  • J45.90: Unspecified asthma
  • J45.901: Unspecified asthma, with (acute) exacerbation
  • J45.902: Unspecified asthma, with status asthmaticus
  • J45.909: Unspecified asthma, uncomplicated
  • J45.99: Other asthma
  • J45.990: Exercise induced bronchospasm
  • J45.991: Cough variant asthma
  • J45.998: Other asthma

ICD-10 Documentation

To assign appropriate ICD-10 codes at the highest level of specificity, the documentation must include severity and complication of the condition. Requirements specified for each level of severity are as follows.


  • Symptoms: 2 or less days per week
  • Night time Awakenings: 2 x per month or less
  • Rescue Inhaler Use: 2 or less days per week
  • Interference with Normal Activity: None
  • Lung function: FEV1>80% predicted and normal between exacerbations

Mild Persistent

  • Symptoms: More than 2 days per week
  • Nighttime Awakenings: 3 – 4 x per month
  • Rescue Inhaler Use: More than 2 days per week, but not daily
  • Interference with Normal Activity: Minor limitation
  • Lung function: FEV1>80% predicted

Moderate Persistent

  • Symptoms: Daily
  • Nighttime Awakenings: More than once per week, but not nightly
  • Rescue Inhaler Use: Daily
  • Interference with Normal Activity: Some limitation
  • Lung function: FEV1 60 – 80% predicted

Severe Persistent

  • Symptoms: Throughout the day
  • Nighttime Awakenings: Nightly
  • Rescue Inhaler Use: Several times per day
  • Interference with Normal Activity: Extremely limited
  • Lung function: FEV1 less than 60% predicted

Physicians must document their observations clearly, including all details so that the coders can assign the correct codes. According to the 2010 statistics of the Centers for Disease Control and Prevention (CDC), there were 14.2 million visits to physician offices, 1.8 million visits to emergency departments and 1.3 million visits to hospital outpatient departments with asthma as primary diagnosis. With millions newly insured since the implementation of the Affordable Care Act (ACA), these figures may increase at the time of ICD-10 roll out. In such a scenario, healthcare providers can seek support for billing and coding services by a medical billing and coding company to meet the copious medical billing and coding requirements.

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