ICD-10 Code G40.A – Absence epileptic syndrome (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G40.A – Absence epileptic syndrome
What it is
G40.A identifies absence epileptic syndrome, a seizure disorder marked by brief episodes of impaired awareness. You use it when the record specifically describes this epilepsy syndrome rather than a single isolated absence seizure.
Clinical signs
Typical features include sudden staring spells, brief unresponsiveness, and rapid return to baseline. Clinical features vary; refer to documentation for syndrome type, seizure pattern, and any associated EEG findings.
When to use this code
Use this code when the clinician documents absence epileptic syndrome, absence epilepsy, or a similar named syndrome. It may apply when the note links recurrent absence seizures to a defined epileptic syndrome. Check documentation if the record only says “seizure” or “spell.”
Do not use for
Do not use it for a single absence seizure without a syndrome diagnosis. Do not assume it applies to other seizure types, syncope, or altered mental status unless the documentation clearly supports absence epileptic syndrome.
Coding tip
Confirm the exact seizure diagnosis in the assessment, because G40.A requires documented absence epileptic syndrome, not just observed staring episodes.