What laboratory tests are performed in epilepsy? | What we need to know

11.12.2025

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An epileptic seizure is a condition caused by abnormal electrical activity in the brain and is characterized by sudden, involuntary contractions of muscles in a particular group of the body. It is initiated by temporary electrical hyperactivity of the brain. There are many epileptic syndromes, and their causes, clinical manifestations, age of onset, course, prognosis, and more vary.

Epilepsy is one of the most common neurological diseases in the world. Approximately 50 million people worldwide are diagnosed with epilepsy, but 70% of these people, with proper and timely treatment, can continue their normal lives and activities without epileptic episodes.

Symptoms and classification of epilepsy

As a result of the disruption of the electrical activity of the brain, various regulatory processes in the brain are disrupted. Along with seizures, epilepsy may develop: temporary changes in consciousness, muscle rigidity, uncontrolled movements of the limbs, psychological disorders, such as fear, anxiety, etc. With each subsequent episode of epileptic discharge, as a rule, the same type of seizure develops.

Depending on the location of the damaged area of the brain and clinical manifestations, epileptic seizures are classified into the following types:

Focal seizures – Occurs in one area of the brain and involves one half of the body or a specific group of muscles. There are two types of focal seizures:
Focal seizures without alteration of consciousness – This type of seizure involves a specific group of muscles, without loss of consciousness. Epileptic seizures may be accompanied by sensory (sensitivity) sensations, such as dizziness, flashing lights in the field of vision, skin sensations, and others.
- Focal seizures with altered consciousness– This form of seizure is called complex partial seizures and is accompanied by a decrease in consciousness. During an epileptic seizure, the patient becomes disoriented in time and space, and repetitive, stereotyped movements – automatisms – occur, such as hand-wringing, chewing, swallowing movements, walking in circles, etc.

The symptoms of focal seizures are often mistaken for symptoms of other neurological disorders, such as migraines, narcolepsy, and mental disorders.

Generalized seizures – Caused by a generalized disturbance in the brain's electrical activity. There are 6 types of generalized seizures:
Nonconvulsive seizures – usually occur in children. They may be characterized by 5-10 seconds of agitation or behavioral changes, with or without motor activity. This type of seizure is recurrent, characterized by brief changes in consciousness, and occurs frequently throughout the day.
Tonic seizures – Causes muscle rigidity and impaired consciousness. Typically, muscle rigidity of the back and limbs is manifested. The muscles are stretched along the longitudinal axis. Consciousness is depressed.
Atonic seizures – Characterized by a 10-15 second, episodic decrease in muscle tone, during which the patient may collapse. This type of seizure is also characterized by a brief change in consciousness.
Clonic seizures – Characterized by repeated rhythmic contractions of a specific group of muscles (neck, arm, leg, etc.).
Myoclonic seizures – Brief contractions of the muscles of the upper torso and limbs. This type of seizure is often part of various epileptic syndromes.
Tonic-clonic seizures – The most dramatic form of epileptic seizure. It begins with a sudden loss of consciousness. This type of seizure includes two phases: tonic – when the muscles of the body are rigid and tense. Clonic – when rhythmic muscle contractions develop – with flexion-extension movements of the limbs. In this process, the control of some physiological processes is disrupted, involuntary urination and/or defecation and tongue biting occur.

Causes and diagnostics of epilepsy

Diagnosis of epileptic syndromes is mainly carried out through electroencephalographic studies, however, in cases of seizures occurring against the background of various metabolic disorders, it is also important to conduct laboratory studies.

creatine kinase – An enzyme found in heart and skeletal muscle cells. Concentrations are much lower in the brain. Creatine kinase concentrations increase during seizures.
electrolytes – To maintain acid-base balance, important electrolytes are: sodium Na, chlorine Cl, potassium K, magnesium Mg, calcium. Electrolyte imbalance affects the electrical activity of the brain and, consequently, the results of treatment.
Creatinine It is an assessment of liver and kidney function, which is an important indicator in epileptic seizures. Creatinine is an indicator of the energy supply of cells, including nerve cells. Patients with epilepsy often have low creatinine levels.
Aspartate aminotransferase AST და Alanine aminotransferase ALT – Liver function tests provide important information not only in assessing general metabolic status, but also allow us to assess the hepatotoxic effects of antiepileptic drugs. Epilepsy treatment is a long process and liver function tests are important to maintain a balance between therapeutic drug concentrations and the development of possible side effects.
Phosphorus in urine – The study allows to determine the excretory function of the kidneys. In addition, it has been confirmed that epileptic seizures are accompanied by hypophosphatemia - that is, a decrease in the concentration of phosphates in the blood and its excretion with urine. This is an important indicator for distinguishing depression of consciousness caused by seizures from other causes of loss of consciousness.
General blood test – It is necessary to detect general processes occurring in the body: allergies, infections, anemia, coagulation processes, etc.
In some cases, a full Metabolic panel examinationto identify possible metabolic disorders that often cause epileptic seizures.
During antiepileptic treatment, when discussing dose adjustment or medication withdrawal, it is essential to: Drug concentration Monitoring In the blood, along with other studies – to obtain maximum therapeutic effect and minimal side effects.

0.8% - 1% of epilepsy cases are genetic in nature. The risk of developing genetic epilepsy syndromes is 2-4 times higher.

Causes of epilepsy also include:

Brain injury
Post-traumatic epilepsy
High fever and anoxic brain damage
stroke
Neurological disorders – dementia, Alzheimer's disease, brain tumors, meningitis, etc.

Laboratory "Synevo" offers biochemical research A wide range: