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Medicare Compliance & Reimbursement

Reader Question:

Know Definitions of ‘Chronic’ May Vary

Question: When should I code for an acute form of a condition as opposed to a chronic form? I can’t find any clarification in ICD-10, but I seem to remember that anything under four weeks is regarded as acute and anything over four weeks would be coded as chronic? Is this true?

SuperCoder Subscriber

Answer: You are correct in saying that there is no guideline in ICD-10 that defines a condition as acute or chronic based on a timeframe. Guideline B.8 (Acute and Chronic Conditions) only tells you to code the acute (or subacute) condition first in a situation where a condition is described as both acute (or subacute) and chronic and there are codes for both “at the same indentation level.” The four-week rule you remember may be from the Includes instruction to I21 (Acute myocardial infarction), which states that the code is to be used for a “myocardial infarction … with a stated duration of 4 weeks (28 days) or less from onset.”

But this does not mean that in general, any condition lasting over four weeks can be regarded as chronic. 
In fact, different organizations use different timeframes for chronic conditions. The National Cancer Institute, for example, defines a chronic disease as “a disease or condition that usually lasts for 3 months or longer” (Source:, while the Centers for Disease Control and Prevention (CDC) defines chronic diseases “conditions that last 1 year or more.” (Source: As there is such a huge discrepancy in the definitions used by professional institutions, it seems clear that you cannot use any one specific time period to determine when acute conditions end and chronic conditions begin.

Ultimately, the decision to define a condition as acute or chronic is up to your providers, and your coding needs to be dependent on their judgement. Should you find indications in a patient’s medical record that point toward a condition being acute or chronic, by all means bring that to your provider’s attention. But if your provider has determined a condition’s severity, that is the way you must code it unless there is good reason not to.