Phenytoin; free
CPT4 code
Name of the Procedure:
Phenytoin; free (also known as Free Phenytoin Level Test)
Summary
The Free Phenytoin Level Test measures the amount of phenytoin in your blood that is not bound to proteins. This test is used to monitor the therapeutic levels of the drug in individuals who are prescribed phenytoin to control seizures.
Purpose
The primary purpose of this test is to ensure that the concentration of phenytoin in the blood is within the therapeutic range. Phenytoin is used to control seizures in individuals with epilepsy, and maintaining proper drug levels can help prevent seizures while minimizing side effects.
Indications
- Patients with epilepsy or seizure disorders who are on phenytoin therapy.
- Individuals experiencing unusual symptoms or side effects potentially related to phenytoin levels.
- Adjustment of phenytoin dosage based on clinical symptoms and lab results.
Preparation
- There are typically no special preparations required for this test.
- Patients may be advised to take their medication at the usual time.
- Inform the healthcare provider of all medications taken, as some can interact with phenytoin.
Procedure Description
- Blood Draw:
- A healthcare professional will clean the skin with an antiseptic.
- A tourniquet is applied to the upper arm to fill the veins with blood.
- A needle is inserted into a vein, usually in the arm, to draw a blood sample.
- The sample is collected into a vial or syringe.
- The tourniquet is removed, and pressure is applied to the site to stop any bleeding.
- Laboratory Analysis:
- The blood sample is sent to a laboratory where it is analyzed to measure the level of free phenytoin.
Duration
The blood draw typically takes about 5 to 10 minutes.
Setting
The procedure is usually performed in a hospital, outpatient clinic, or a laboratory setting.
Personnel
- Phlebotomist or nurse (for blood draw)
- Laboratory technician (for sample analysis)
Risks and Complications
- Mild pain or bruising at the needle insertion site.
- Rarely, infection or excessive bleeding.
Benefits
- Accurate monitoring of phenytoin levels helps in adjusting the dosage for optimal seizure control.
- Early detection of toxic or subtherapeutic drug levels can prevent complications.
Recovery
- No special recovery is required.
- Patients can resume normal activities immediately after the blood draw.
- Any discomfort at the puncture site usually resolves quickly.
Alternatives
- Total phenytoin level test (measures both bound and unbound phenytoin).
- Other antiepileptic drug monitoring options if phenytoin is not suitable.
Patient Experience
- Most patients experience minimal discomfort during the blood draw.
- Mild soreness or bruising may occur at the puncture site but typically resolves quickly.
- Patients are advised to follow up with their healthcare provider to discuss the results and any necessary adjustments in medication.