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The Phenytoin Free and Total Serum Test measures how much phenytoin is in your blood to help keep treatment safe and effective. You may hear it called a Dilantin level, phenytoin level, or phenytoin therapeutic drug monitoring. You can book this test at participating labs on LabFinder.
A phenytoin TDM test and phenytoin blood level show two numbers. The total level includes all the drug in your blood. The free level shows the part not bound to proteins and is the part that works in the body. Together, they help your doctor adjust your dose.
Common reasons: starting phenytoin and setting the right dose, checking after a dose change, symptoms that may mean a high level like sleepiness or balance problems, ongoing seizures that may mean a low level, liver or kidney concerns, and checking for drug interactions that can raise or lower levels.
Plan about 10 to 20 minutes at the lab. You will check in, confirm your details, and have a small blood sample taken from your arm. A bandage is placed and you can usually return to normal plans right away.
Yes, this is a quick, routine blood draw and is considered very safe. You might feel a quick pinch, notice a small bruise, or feel a little lightheaded for a moment afterward, but those effects usually fade quickly. Be sure to tell the staff if you take blood thinners, have a bleeding disorder, or if you have fainted during blood draws before. They will take extra care to keep you comfortable. Timing the draw in relation to your last dose can affect the result that day, so follow your doctor’s timing instructions.
Ask about timing: Many doctors want a trough level, which is right before your next dose. Take meds as directed: Do not skip or change doses unless your doctor says so. Bring details: Write down your dose and the exact time of your last dose. Share your med list: Some drugs and supplements change phenytoin levels. Stay hydrated: Drinking water can make the blood draw easier.
Seizure control while on phenytoin, signs of possible toxicity such as confusion or unsteady walking, suspected low levels when seizures break through, liver or kidney issues that can change levels, and possible interactions with other medicines. Results are always read in context. Your doctor will review your numbers along with your history and symptoms before advising next steps.
With LabFinder, you can compare locations, view time slots, and book online at participating labs. It is easy to search for a convenient location in your area or by city or ZIP. Coverage varies by plan and provider, so check with your insurer and the lab when you schedule.
Book on LabFinder: find a lab today on our lab finder and request a test doctor guided.
The information on this page and throughout the LabFinder website and mobile app is for general informational purposes only. It is not intended to serve as medical advice, diagnosis, or treatment. For personalized medical advice or specific health concerns, please consult your healthcare provider directly.
Booking a Phenytoin Free and Total Serum Test is easy using LabFinder. Just choose your location and enter your insurance information to find the closest Phenytoin Free and Total Serum Test near you.
To make a same-day appointment for a Phenytoin Free and Total Serum Test, just choose your location and your insurance information to find the closest Phenytoin Free and Total Serum Test location near you. If there's availability for a same-day appointment at a nearby lab location, then you will be able to book it easily through LabFinder.
LabFinder allows you to easily schedule a Phenytoin Free and Total Serum Test. You can search by location and insurance to easily book a Phenytoin Free and Total Serum Test near you.
LabFinder allows you to easily make an appointment for a Phenytoin Free and Total Serum Test online. To make an appointment for a Phenytoin Free and Total Serum Test online, just choose your location and your insurance information to find the closest Phenytoin Free and Total Serum Test near you.
Yes, you can get a Phenytoin Free and Total Serum Test without insurance. LabFinder allows you to search and select "Self-Pay" when booking a Phenytoin Free and Total Serum Test. While pricing for the test may not be immediately available, please check by calling the lab company directly for pricing.
