ICD-10 Code D89.44 – Hereditary alpha tryptasemia (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D89.44 – Hereditary alpha tryptasemia
What it is
D89.44 identifies hereditary alpha tryptasemia, an inherited condition associated with increased alpha tryptase gene copies. It may lead to elevated baseline tryptase and a range of mast cell-related symptoms.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include flushing, itching, abdominal discomfort, diarrhea, and symptoms suggestive of allergic or mast cell activation disorders.
When to use this code
Use D89.44 when the provider documents hereditary alpha tryptasemia or confirms the diagnosis in the record. It is appropriate when the condition is being evaluated as the cause of persistent elevated tryptase or recurrent mast cell-type symptoms.
Code it only when the documentation supports this specific inherited disorder, not just nonspecific allergy or mast cell symptoms. Check documentation if the note describes elevated tryptase without a confirmed hereditary diagnosis.
Do not use for
Do not use this code for general mastocytosis, anaphylaxis, or isolated elevated tryptase without hereditary alpha tryptasemia documented. Check documentation when the diagnosis is uncertain.
Coding tip
Assign D89.44 only when the provider links the symptoms or test findings to hereditary alpha tryptasemia.