Please Remove Adblock
Adverts are the main source of Revenue for DoveMed. Please remove adblock to help us create the best medical content found on the Internet.

Anticonvulsants Blood Test

Last updated July 27, 2019

Approved by: Maulik P. Purohit MD, MPH

The Anticonvulsants Blood Test helps determine the level of anticonvulsants in blood. It is used when adjusting the initial dose and to ensure that anticonvulsant levels stay within an acceptable range.

What are other Names for this Test? (Equivalent Terms)

  • Anticonvulsant Levels Blood Test
  • Anticonvulsant Medications Blood Test
  • Anti-Seizure Medications Blood Test

What is Anticonvulsants Blood Test? (Background Information)

  • Anticonvulsants are medications used to treat seizures. They are also useful in the treatment of other psychiatric conditions such as bipolar disorder.
  • Seizures are episodes of abnormal and excessive brain cell activity; they may last several seconds to even 5 minutes. Often, the cause of a seizure is unknown. A seizure may occur as result of a nervous system disorder, called epilepsy. They may also occur following a brain surgery
  • During a seizure, an individual may convulse or display other uncontrolled physical behaviors. Such seizures are said to be convulsive and convulsive seizures are the most common seizures
  • Alternatively, non-convulsive seizures do not exhibit this uncontrolled physical behavior. Instead, an individual experiencing this seizure type may momentarily lapse out of consciousness, effectively “zoning out”
  • Brain cells communicate to each other and to other cells, through electrical signals. During a seizure, brain cells are rendered excessively conductive. The brain cells that are over-conductive transfer electrical signals too freely. This results in the derailment of their communications system, causing either convulsive or non-convulsive effects of seizures
  • Anticonvulsants treat seizures and other psychiatric conditions by dampening the activities of brain cells. This reduces the sky-high conductivity of brain cells to more functional levels
  • Like every other drugs, anticonvulsants must be kept within a certain range to prevent certain unwanted effects. If the levels are too high, toxicity may result; if the levels are too low, the drug may not successfully ward-off a seizure attack
  • The Anticonvulsants Blood Test helps determine the level of anticonvulsants in blood. It is used when adjusting the initial dose and to ensure that anticonvulsant levels stay within an acceptable range

What are the Clinical Indications for performing the Anticonvulsants Blood Test?

Following are the clinical indications for performing the Anticonvulsants Blood Test include monitoring anticonvulsant therapy.

How is the Specimen Collected for Anticonvulsants Blood Test?

Following is the specimen collection process for Anticonvulsants Blood Test:

Sample required: Blood

Process of obtaining blood sample in adults:

  • A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
  • The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
  • The needle cap is removed and is held in line with the vein, pulling the skin tight
  • With a small and quick thrust, the vein is penetrated using the needle
  • The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
  • The wrap band is removed, gauze is placed on the collection site, and the needle is removed
  • The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
  • The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal

Preparation required: No special preparation is needed prior to the test.

What is the Significance of the Anticonvulsants Blood Test Result?

The significance of the Anticonvulsants Blood Test result is explained:

  • A high test value may indicate anticonvulsant toxicity, which is marked by:
    • Lower back pain
    • Fatigue
    • Nausea
    • Vomiting
    • Diarrhea
    • Altered mental status
    • Abnormal heart rate
    • Abnormal breathing
  • A low test value may indicate more anticonvulsant is necessary to achieve a therapeutic dose

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • Some anticonvulsant medications, such as Tegretol, are known teratogens. This means that they may cause birth defects and other abnormalities. Caution should be taken when administering these medications during pregnancy

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

The following DoveMed website links are some useful resources for additional information:






Please visit our Laboratory Procedures Center for more physician-approved health information:


References and Information Sources used for the Article:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Oct. 31, 2015
Last updated: July 27, 2019