ICD-10 Code D81.4 – Nezelof’s syndrome (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D81.4 – Nezelof’s syndrome
What it is
D81.4 identifies Nezelof’s syndrome, a form of primary immunodeficiency. It is used when documentation specifies this inherited immune disorder rather than a broader combined immunodeficiency.
Clinical signs
Clinical features vary; refer to documentation. Typical references describe recurrent infections and impaired immune function, often with T-cell dysfunction or combined immune deficiency findings.
When to use this code
Use D81.4 when the provider documents Nezelof’s syndrome by name, or clearly describes the condition as this specific immunodeficiency. It may also fit when records confirm the diagnosis without a more specific subtype. If the chart only says “immunodeficiency,” check documentation before coding.
Do not use for
Do not use this code for acquired immunodeficiency, such as HIV-related disease, or for unspecified immune deficiency without Nezelof’s syndrome documented. Check documentation if the diagnosis is only suspected.
Coding tip
Code D81.4 only when the record supports the named syndrome; otherwise, select the most specific documented immunodeficiency code.