Question: How do I distinguish between mild, moderate, and severe persistent asthma diagnoses? What does the provider need to document in order to reach one of these diagnoses? Oregon Subscriber Answer: Despite the fact that physicians can report asthma of various degrees of chronicity and severity, coders more often than not have to resort to J45.909 (Unspecified asthma, uncomplicated) simply due to a lack of documentation. Providers can classify asthma as mild intermittent, mild persistent, moderate persistent, and severe persistent. Differentiating between these classifications depends on the following: When choosing between asthma classifications, mind these rules regarding the above characteristics. If the physician and/or nurse practitioner (NP) does not document one or more of the above criteria, you should code the asthma as unspecified: Mild intermittent: Mild persistent: Moderate persistent: Severe persistent: Remember: The physician or NP must specifically document "status asthmaticus" in order for you to code it. However, you may code asthma with acute exacerbation if the physician documents any acute symptoms of difficulty breathing, wheezing, chest tightness, and/or coughing alongside the asthma diagnosis.