Blood, Metabolic, and Genetic Tests

Alongside EEG and imaging, various laboratory tests are used to look into the cause of epilepsy and to carry out treatment safely. This chapter explains why those tests are ordered.

Blood Tests

The blood tests ordered at the initial evaluation look for temporary or correctable causes that could lead to a seizure: low blood sugar, imbalances in calcium or sodium, markers of infection, and so on. In addition, before starting medication, baseline values such as liver and kidney function and the blood count are recorded; this way, possible changes can be monitored during treatment.

Metabolic Tests

Metabolic disorders are investigated especially in epilepsies that begin in the first years of life, are unexplained, or are resistant to treatment. There is an important reason for this: some metabolic causes can improve dramatically with treatments aimed directly at the target (for example, a specific vitamin, a special diet, or restricting a particular substance). Not missing these rare but treatable conditions is what makes a detailed workup worthwhile.

Genetic Tests

Genetic tests have taken on an increasingly important role in pediatric epilepsy in recent years. Genetic testing is ordered especially in cases that begin early, are accompanied by developmental involvement, or where a specific syndrome is suspected.

Why Is Genetic Testing Done?

• To make a definite diagnosis: Some epilepsies are due to a specific gene change. Identifying this can bring a long, uncertain search to an end.
• To choose the right treatment: Some genetic diagnoses directly show which medication will work or which one should be avoided. For example, in Dravet syndrome, avoiding certain medications only becomes clear with the genetic diagnosis.
• To anticipate the course: A genetic diagnosis informs the family and the doctor about the likely course of the condition.
• For family planning: In some situations, genetic counseling sheds light on the family's future decisions.

Realistic Expectations About Genetic Testing

Genetic testing is not done in every child and does not always give an answer. A normal test result does not definitively rule out a genetic cause.

Genetic results are sometimes complex and should be evaluated together with genetic counseling. To interpret the results, be sure to talk in detail with your doctor; don't draw your own conclusions based on gene names you find on the internet.