ICD-10 Code E73.9 – Lactose Intolerance, Unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E73.9 – Lactose intolerance, unspecified
What it is
E73.9 identifies lactose intolerance when the specific type is not documented. It means the patient cannot digest lactose well, leading to symptoms after milk or dairy intake.
Clinical signs
Typical findings include abdominal bloating, gas, cramps, and diarrhea after lactose exposure. Clinical features vary; refer to documentation.
When to use this code
Use E73.9 when the record states lactose intolerance but does not specify a congenital, acquired, or other subtype. It also fits when the clinician documents intolerance to lactose-containing foods without further detail. You should confirm that the note supports an intolerance diagnosis rather than a temporary digestive complaint.
Do not use for
Do not use this code for milk allergy, nonspecific food intolerance, or abdominal symptoms alone. Check documentation if the diagnosis is uncertain.
Coding tip
Assign the unspecified code only when the provider documents lactose intolerance without a more specific category.