ICD-10 Code F03.C – Unspecified Dementia, Severe (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code F03.C – Unspecified dementia, severe
What it is
F03.C identifies severe dementia when the type is not specified in the documentation. Use it for advanced cognitive decline with major loss of independent function, but without a documented underlying dementia subtype.
Clinical signs
Clinical features vary; refer to documentation. Severe dementia commonly includes marked memory loss, disorientation, impaired communication, and dependence on others for daily care.
When to use this code
Use this code when the record clearly states severe dementia and does not name Alzheimer disease, vascular dementia, or another specific cause. It also fits when the provider documents dementia severity but leaves the etiology unspecified.
If the chart contains a more specific dementia diagnosis, code that condition instead. Check documentation for any associated behavioral disturbance or other recorded details that may require additional coding.
Do not use for
Do not use F03.C when the dementia type is identified or when the documentation supports a milder stage. Do not assume severity from confusion alone; check documentation.
Coding tip
Query the provider if severity is clear but the dementia type is missing, because specificity may change the final code.