ICD-10 Code A04.3 – Enterohemorrhagic Escherichia coli infection (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code A04.3 – Enterohemorrhagic Escherichia coli infection
What it is
This code identifies infection caused by enterohemorrhagic Escherichia coli, a strain of E. coli associated with bloody diarrheal illness. Use it when the record specifically documents this organism or an equivalent diagnosis.
Clinical signs
Typical findings include acute diarrhea that may become bloody, abdominal cramping, and signs of gastrointestinal infection. Clinical features vary; refer to documentation, especially when the organism is confirmed or strongly suspected.
When to use this code
Use A04.3 when the provider documents enterohemorrhagic E. coli infection, EHEC infection, or a clearly equivalent term. Apply it for encounters focused on this specific infectious diagnosis, even if the note also mentions diarrhea or colitis. Check documentation when the organism is not explicitly identified.
Do not use for
Do not use this code for unspecified infectious diarrhea or for other E. coli infections without enterohemorrhagic documentation. If the chart only says “gastroenteritis” or “colitis,” check documentation for the causal organism.
Coding tip
Code the organism documented by the provider; if EHEC is not named, do not assume A04.3.