ICD-10 Code D81.2 – Severe combined immunodeficiency [SCID] with low or normal B-cell numbers (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D81.2 – Severe combined immunodeficiency [SCID] with low or normal B-cell numbers
What it is
D81.2 identifies a severe inherited immune disorder in which both T-cell function and overall immune defense are profoundly impaired, while B-cell numbers are low or normal. It is used for the SCID subtype defined by this immune pattern.
Clinical signs
Patients typically have recurrent, severe, or unusual infections early in life, along with poor immune response. Clinical features vary; refer to documentation for the specific SCID subtype and immune-cell findings.
When to use this code
Use D81.2 when the provider documents SCID with low or normal B-cell numbers, or an equivalent description of this subtype. You may also use it when the record clearly supports this diagnosis from specialist evaluation and the documentation is specific.
Do not infer the code from general immunodeficiency alone. If the chart only says SCID without B-cell detail, check documentation before assigning this code.
Do not use for
Do not use D81.2 for other primary immunodeficiencies, acquired immunodeficiency, or SCID subtypes with different B-cell patterns. Check documentation if the subtype is unspecified.
Coding tip
Confirm the exact SCID subtype in the provider note before coding, because B-cell status determines whether D81.2 is appropriate.