D89.43: Secondary mast cell activation
D89.43 is the billable ICD-10-CM diagnosis code for Secondary mast cell activation. It is a fully specified code, so it can be reported on a claim (subject to clinical documentation and your payer's rules).
Frequently asked questions
What is ICD-10-CM code D89.43?
D89.43 is the ICD-10-CM diagnosis code for Secondary mast cell activation. It belongs to category D89 (Other disorders involving the immune mechanism, not elsewhere classified).
Is D89.43 a billable code?
Yes. D89.43 is a billable, fully specified ICD-10-CM code, so it can be used on a claim (subject to documentation and payer rules).
What category does D89.43 belong to?
D89.43 is part of ICD-10-CM category D89 — Other disorders involving the immune mechanism, not elsewhere classified, which has 48 billable codes.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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