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Tests for epilepsy

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Tests for epilepsy

Blood tests, an Electroencephalogram (EEG) and scans are used to gather information for a diagnosis. Tests on their own cannot confirm or rule out epilepsy.

Reasons for tests

Your neurologist or specialist may ask you to have some tests to get extra information about your seizures. The tests are usually done by a technician (a person who is trained to do them).

The results from the tests are then passed back to the neurologist to see what they show. The results may indicate that you have epilepsy and may also show a cause for your epilepsy.

No test can say for certain whether you do or do not have epilepsy. But when information from the tests is added to the description of what happens during your seizures, this builds up a clearer picture of what happened. This can help with the diagnosis and when choosing treatment.

There are a number of tests that can help rule out other causes. These include:

Blood tests

A sample of blood will usually be taken from your arm with a syringe. The sample is used to check your general health and to rule out other possible causes for your seizures, such as low blood sugar levels or diabetes.

Electrocardiogram (ECG)

An ECG is used to record the electrical activity of the heart. This is done by sticking electrodes (a bit like plasters) to the arms, legs and chest. These electrodes pick up the electrical signals from the heart.

An ECG does not give out electrical signals, so having one doesn’t hurt. An ECG can help to rule out the seizure being caused by the way the heart is working.

Brain scans

A brain scan may help to find the cause of your seizures. The two common types of brain scan are Magnetic Resonance Imaging (MRI) and Computerised Axial Tomography (CT or CAT).


When someone has had seizures, and it is thought that they might have epilepsy, there are various tests that their specialist might ask for. Two of these tests are the electroencephalogram (EEG) and MRI.


An MRI scan will not say for certain whether the person has epilepsy or not. But alongside other information, these might help the specialist to decide if epilepsy is a likely cause of the seizures.

Information updated: October 2021

Tests for epilepsy

Brain scans

In order for a person to be suitable for surgery, it is necessary to confirm that seizures are arising from one part of the brain and that it is safe to remove this part. This requires many tests including MRI brain scans.

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