D81: Combined immunodeficiencies
Codes under D81 (Combined immunodeficiencies). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| D81.0 | Severe combined immunodeficiency [SCID] with reticular dysgenesis | ✓ |
| D81.0 | Severe combined immunodeficiency [SCID] with reticular dysgenesis | ✓ |
| D81.1 | Severe combined immunodeficiency [SCID] with low T- and B-cell numbers | ✓ |
| D81.1 | Severe combined immunodeficiency [SCID] with low T- and B-cell numbers | ✓ |
| D81.2 | Severe combined immunodeficiency [SCID] with low or normal B-cell numbers | ✓ |
| D81.2 | Severe combined immunodeficiency [SCID] with low or normal B-cell numbers | ✓ |
| D81.3 | Adenosine deaminase [ADA] deficiency | — |
| D81.3 | Adenosine deaminase [ADA] deficiency | — |
| D81.4 | Nezelof's syndrome | ✓ |
| D81.4 | Nezelof's syndrome | ✓ |
| D81.5 | Purine nucleoside phosphorylase [PNP] deficiency | ✓ |
| D81.5 | Purine nucleoside phosphorylase [PNP] deficiency | ✓ |
| D81.6 | Major histocompatibility complex class I deficiency | ✓ |
| D81.6 | Major histocompatibility complex class I deficiency | ✓ |
| D81.7 | Major histocompatibility complex class II deficiency | ✓ |
| D81.7 | Major histocompatibility complex class II deficiency | ✓ |
| D81.8 | Other combined immunodeficiencies | — |
| D81.8 | Other combined immunodeficiencies | — |
| D81.9 | Combined immunodeficiency, unspecified | ✓ |
| D81.9 | Combined immunodeficiency, unspecified | ✓ |
| D81.30 | Adenosine deaminase deficiency, unspecified | ✓ |
| D81.30 | Adenosine deaminase deficiency, unspecified | ✓ |
| D81.31 | Severe combined immunodeficiency due to adenosine deaminase deficiency | ✓ |
| D81.31 | Severe combined immunodeficiency due to adenosine deaminase deficiency | ✓ |
| D81.32 | Adenosine deaminase 2 deficiency | ✓ |
| D81.32 | Adenosine deaminase 2 deficiency | ✓ |
| D81.39 | Other adenosine deaminase deficiency | ✓ |
| D81.39 | Other adenosine deaminase deficiency | ✓ |
| D81.81 | Biotin-dependent carboxylase deficiency | — |
| D81.81 | Biotin-dependent carboxylase deficiency | — |
| D81.82 | Activated Phosphoinositide 3-kinase Delta Syndrome [APDS] | ✓ |
| D81.82 | Activated Phosphoinositide 3-kinase Delta Syndrome [APDS] | ✓ |
| D81.89 | Other combined immunodeficiencies | ✓ |
| D81.89 | Other combined immunodeficiencies | ✓ |
| D81.810 | Biotinidase deficiency | ✓ |
| D81.810 | Biotinidase deficiency | ✓ |
| D81.818 | Other biotin-dependent carboxylase deficiency | ✓ |
| D81.818 | Other biotin-dependent carboxylase deficiency | ✓ |
| D81.819 | Biotin-dependent carboxylase deficiency, unspecified | ✓ |
| D81.819 | Biotin-dependent carboxylase deficiency, unspecified | ✓ |
Frequently asked questions
What is ICD-10-CM code D81?
D81 is an ICD-10-CM category covering Combined immunodeficiencies. It contains 40 more specific diagnosis codes, 34 of which are billable.
Is D81 a billable code?
No — D81 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example D81.0 — Severe combined immunodeficiency [SCID] with reticular dysgenesis). 34 of the 40 codes under D81 are billable.
What codes fall under D81?
D81 includes D81.0, D81.0, D81.1, D81.1, D81.2, plus 35 more. See the full list with descriptions and billable status above.
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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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