What's this test for?

This test is ideal if you're experiencing unexpected drowsiness, confusion, or other side effects that might be linked to diphenhydramine (a common antihistamine found in allergy and sleep medications). It's also useful if you need to confirm how much of the medication is in your system, whether for safety monitoring or to check if levels are too high or too low. This test gives a clear picture of your current diphenhydramine level so you can understand what's going on in your body.

What happens after I get my results?

Your results will show up in your online account, with the normal range clearly explained next to your value so you know exactly where you stand. If your level is higher or lower than expected, the report will point out what that means and suggest simple next steps, like adjusting medication timing or spacing out doses. A full downloadable lab report is always available in your account, and you can use the trends feature to track your levels over time if you're retesting. If your result is dangerously high and you're having severe symptoms like extreme drowsiness or trouble breathing, seek medical care right away.

Who should consider this test?

Anyone who takes diphenhydramine regularly, whether for allergies, sleep, or motion sickness, and wants to know how much is building up in their system should consider this test. It's also helpful for people who've had unusual reactions to antihistamines or who take multiple medications that might interact with diphenhydramine. People who suspect accidental overuse or want a baseline before adjusting their medication routine can benefit as well.

What symptoms indicate I may need this test?

Signs that you might want to check your diphenhydramine level include ongoing drowsiness or grogginess, dizziness, dry mouth, blurred vision, confusion, or trouble concentrating even after the medication should have worn off. Rapid heartbeat, difficulty urinating, or unusual agitation can also be worth checking out. If these symptoms are severe or you think you've taken too much, treat it as urgent and seek medical care.

When will I get my results?

Results are typically ready within about 7 days after your sample is collected at the lab. You'll get a notification as soon as your report is available in your online account, where you can view your value alongside the normal range and a plain-language explanation.

How can I naturally support recovery from antihistamine side effects?

Staying well hydrated helps your body clear diphenhydramine more efficiently. Getting extra rest, avoiding alcohol and other sedating substances, and giving your body time between doses can also reduce buildup. Simple habits like taking the medication at the same time each day and avoiding doubling up on doses go a long way toward keeping levels in a safe range.

What does high diphenhydramine mean?

A high level usually means more of the medication is in your system than expected, which could be from taking it too frequently, taking a higher dose than recommended, or your body processing it more slowly than usual. This can lead to stronger side effects like heavy drowsiness, confusion, or a fast heartbeat. If your result is high and you're feeling unwell, cutting back on dosing frequency and staying hydrated can help, but severe symptoms need urgent medical attention.

What causes high or low diphenhydramine levels?

High levels are often caused by taking doses too close together, using more than the recommended amount, or combining it with other sedating medications. Low or undetectable levels usually just mean it's been a while since your last dose or that the medication has already been cleared from your system. Things like liver function and individual metabolism speed can also affect how quickly levels rise or fall.

How often should I retest?

If you're using diphenhydramine regularly and monitoring for safety, retesting every few weeks or after any dose changes can help you stay on top of things. If you're just checking after a single incident or symptom episode, one test is usually enough unless symptoms continue. Use the trends feature in your account to keep an eye on changes over time.

What should I do if my results are abnormal?

If your level is higher than expected, consider spacing out your doses more, sticking to recommended amounts, and avoiding other sedating substances like alcohol. Give your body time to clear the medication and retest if you want to confirm it's back in range. If you're experiencing severe symptoms like difficulty breathing, extreme confusion, or a very fast heartbeat, seek medical care immediately rather than waiting on a retest.

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.

Diphenhydramine Test - Antihistamine 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]

Diphenhydramine Blood Test — Antihistamine Level Check

Diphenhydramine, Serum/Plasma

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.

Find a lab near you

Diphenhydramine Blood Test — Antihistamine Level Check

Prescription & all lab fees included

Doctor's guidance included

Fast & convenient

1,000,000+ blood tests later, here's what our customers say