What's this test for?

This test is ideal if you're taking phenytoin to control seizures and need to make sure your dose is working safely and effectively. It's especially useful if you have kidney problems, low albumin levels, or a condition like nephrotic syndrome, since these can change how phenytoin behaves in your body. It also helps if you've had unexpected seizures or side effects and need to check whether your medication level is the cause.

What happens after I get my results?

Your results will show up in your account with a clear explanation of the normal range for free phenytoin so you can see exactly where your level falls. If your level is outside the expected range, the report will explain what that might mean, and you can use the trends feature to track your levels over multiple tests to spot patterns tied to dosage changes or symptoms. A downloadable lab report is always available in your account for your records. If a result looks dangerously high or you're experiencing severe symptoms like confusion or trouble breathing, seek medical care right away.

Who should consider this test?

Anyone currently taking phenytoin for seizure control, especially if they have kidney disease, low albumin, or other conditions that affect how proteins bind drugs in the blood, should consider this test. It's also useful for people whose seizures aren't well controlled, who are experiencing possible side effects, or who are on multiple medications and want to confirm phenytoin is at a safe, effective level. People with uremia or nephrotic syndrome benefit most because their total phenytoin readings can be misleading.

What symptoms indicate I may need this test?

Signs like new or worsening seizures, unusual drowsiness, dizziness, slurred speech, or uncoordinated movements can all point to a phenytoin level that's too high or too low. Confusion, blurred or double vision, and tremors are also common signs of levels that need checking. If you notice any of these changes after adjusting your dose or starting a new medication, testing can help clarify what's happening.

What is free phenytoin and why does it matter?

Free phenytoin is the portion of the drug that isn't attached to proteins in your blood and is available to actually work on your brain to prevent seizures. Measuring it matters because factors like kidney disease or low albumin can throw off standard total phenytoin readings, making the free level a more accurate picture of how much active drug is really affecting you. This gives a truer sense of whether your dose is right.

What does high free phenytoin mean?

A high free phenytoin level means more active drug is circulating and reaching your brain than intended, which can cause side effects like unsteady walking, slurred speech, confusion, or drowsiness. This can happen if your dose is too high, if your body isn't clearing the drug efficiently, or if binding proteins are lower than normal. Simple next steps include reviewing your current dose and any new medications with the instructions provided in your account, and retesting after any changes.

What does low free phenytoin mean?

A low free phenytoin level suggests there may not be enough active drug available to prevent seizures effectively, which raises the risk of breakthrough seizures. This can happen from missed doses, drug interactions, or your body processing the medication faster than usual. If you notice more frequent seizures alongside a low reading, it's worth reviewing your dosing schedule and retesting to confirm the trend.

What causes abnormal free phenytoin levels?

Abnormal levels are often caused by inconsistent dosing, missed or doubled-up doses, or interactions with other medications that change how phenytoin is processed. Health conditions like kidney disease or low albumin can also shift how much phenytoin is free versus protein-bound, even when the total dose stays the same. Diet, liver function, and changes in body weight can play a role too.

How often should I retest?

Retesting frequency really depends on how stable your seizures and dosing have been; many people check levels every few months once things are steady, or sooner after any dose change, new medication, or noticeable symptom shift. Using the trends feature in your account can help you and track whether your levels stay consistent over time. If you're newly started on phenytoin or recently changed your regimen, more frequent checks are typically helpful.

What should I do if my results are abnormal?

Start by comparing your result to the normal range explained in your report to see how far off it is. Simple steps include reviewing your dosing routine for missed or extra doses, checking with your pharmacist about interactions with any new medications or supplements, and scheduling a retest to confirm the result. If you're having severe symptoms like ongoing seizures, confusion, or trouble breathing, seek emergency medical care immediately.

Getting your blood test with us is easy, private & backed by the power of science.Long story short: In the test options, use the filters or search box to narrow your choices and find the test you want. If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test. Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout. If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want. When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system. Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way. You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy! If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com and we'll gladly help you.

How do I know which test to get?

In the test options, find the test you want. If you’re not sure which test to get, we can lend a hand in finding the right option. Just text or call us at 754-799-7833, email us at support@privatemdlabs.com, and we'll gladly help you. We've got your back and reply quickly.

When will my lab results be available?

Most test results will be available within 1–3 business days. Once they're ready, we'll send an email and text message to let you know. After your blood draw, just hang tight and don't worry – we'll keep you updated and in the loop! If you have any further questions, please text us at 754-799-7833 or email support@privatemdlabs.com, and we'll gladly help you.

Is it possible to make changes to my lab order if I made a mistake with the name, date of birth, or any other details?

Absolutely! We totally understand that errors can happen. No worries, we're here to help you. Just reach out to us via text at 754-799-7833 or shoot us an email at support@privatemdlabs.com. Remember to include your order number and let us know the correct information you’d like to update. Our awesome team will jump right in and make sure everything is sorted out and accurate for you. There are no changes necessary if your address is wrong on the requisition though. We don’t mail anything out. Our lab requires an address to be listed to generate an order.

Do you accept health insurance?

Only HSA & FSA is accepted. Our services are strictly self-pay and cannot be submitted to your health insurance provider except for Health Savings Accounts or Flexible Savings Accounts. This policy applies to all insurance companies, including federal health insurance programs like Medicare. If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com.

Can I cancel my order?

Yes. We get it – sometimes your needs change. As long as your samples haven’t been collected yet, we’re happy to help you cancel your order. If you have any further questions, please text us at 754-799-7833 or email support@privatemdlabs.com. You can read more about our cancellation policy here.

How can I find a lab location near me?

During the ordering process, you’ll be able to select a specific lab near you, with no strings attached! You can switch it up later easily and visit any of our authorized locations as long as it’s the same lab company you selected your test for (Quest Diagnostics or Labcorp). Before you proceed with your order, feel free to browse through all our lab locations here. This will give you the peace of mind of knowing that there's a lab nearby your home, office or your favorite gym. If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com and we'll gladly help you.

Free Phenytoin Test - Epilepsy Drug Level Monitoring

Getting your blood test with us is easy, private & backed by the power of science.

Long story short:

In the test options, use the filters or search box to narrow your choices and find the test you want.
If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test.
Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout.
If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want.
When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system.
Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way.
You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy!

754-799-7833

[email protected]

Free Phenytoin Blood Test - Seizure Medication Monitoring

Phenytoin, Free

Prescription & all lab fees included

Doctor's guidance included

Fast & convenient

Prescription & all lab fees included

Doctor's guidance included

Fast & convenient

What's this test for?

What happens after I get my results?

Who should consider this test?

Here’s why 1,000,000+ customers chose us for affordable hassle-free private blood testing.

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Free Phenytoin Blood Test - Seizure Medication Monitoring

Prescription & all lab fees included

Doctor's guidance included

Fast & convenient

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