Abnormal electroencephalogram [EEG]

This code indicates an abnormal finding on an electroencephalogram (EEG), a diagnostic test that measures electrical activity in the brain. It signifies that the brain's electrical patterns deviate from normal parameters, suggesting potential neurological dysfunction. This finding is not a diagnosis itself but an indicator requiring further investigation.

Use this code when an EEG report explicitly states "abnormal EEG" or describes specific abnormal patterns (e.g., epileptiform discharges, focal slowing, generalized slowing) without a definitive neurological diagnosis yet established. Documentation must clearly indicate the performance of an EEG and the physician's interpretation of its findings as abnormal.

• Do not code this as a primary diagnosis if a definitive neurological condition (e.g., epilepsy, encephalopathy) has been established.
• Sequence this code after the primary reason for the EEG, if known, or as the primary diagnosis if the abnormal EEG is the sole finding.
• Avoid using this code if the EEG is described as "normal" or "within normal limits."