What's this test for?

This test is ideal if you're taking isoniazid for tuberculosis treatment or prevention and need to check how much of the medication is in your blood. It helps confirm the drug is at a safe and effective level, especially if you're not responding to treatment as expected or you're experiencing side effects. It's also useful if there are concerns about how your body is processing the medication.

What happens after I get my results?

Your results will show up in your account with the normal range clearly explained next to your value. If your level falls outside the expected range, simple next steps like adjusting timing of your dose or scheduling a retest are usually recommended, and if your result is dangerously high or you have severe symptoms, seek medical care right away. You can download a standard lab report from your account at any time, and the trends feature lets you track your isoniazid levels over multiple tests to see how they change.

Who should consider this test?

Anyone currently on isoniazid therapy for active tuberculosis or as a preventive treatment may want this test, especially if there are questions about whether the dose is working properly. It's also helpful for people who process medications unusually slowly or quickly, since this can affect how much drug builds up in the blood. If you've noticed side effects or your treatment doesn't seem to be working, this test can provide useful information.

What symptoms indicate I may need this test?

Signs like nausea, loss of appetite, yellowing skin or eyes, tingling in your hands or feet, or unusual tiredness while on isoniazid could mean your levels need checking. Ongoing tuberculosis symptoms despite treatment can also be a sign that your drug levels aren't in the right range. If you notice any of these, testing can help clarify what's happening in your body.

How can I naturally support liver health while on isoniazid?

Since isoniazid is processed by your liver, simple habits like avoiding alcohol, eating balanced meals, and staying hydrated can help support liver function during treatment. Getting enough sleep and avoiding unnecessary over-the-counter medications can also reduce stress on your liver. These habits work alongside your treatment rather than replacing it.

When will I get my results?

Results are typically ready within about 7 days of your blood draw. Once ready, they'll be posted directly to your online account where you can view and download them.

What does a high isoniazid level mean?

A higher than expected level may mean your body isn't breaking down the medication as quickly as usual, which can raise the risk of side effects like liver irritation or nerve tingling. This might mean a dose adjustment is worth discussing, and simple steps like avoiding alcohol can help reduce added strain on your liver in the meantime. Retesting after any dose change can confirm your levels have moved into a safer range.

What does a low isoniazid level mean?

A lower than expected level could mean the medication is being processed too quickly by your body, or that a dose was missed or taken incorrectly, which may reduce how well it's working against tuberculosis. Taking your medication exactly as prescribed and at consistent times each day can help keep levels steady. If levels stay low, retesting can help track whether adjustments are making a difference.

How often should I retest?

Retesting frequency depends on your treatment plan, but many people on isoniazid check levels every few weeks early in treatment or whenever a dose is changed. If you're feeling well and your levels have been stable, testing less often may be reasonable. Using the trends feature in your account can help you and your care team, err, help you keep track of whether more frequent testing makes sense.

What should I do if my results are abnormal?

If your level is outside the normal range, start by reviewing how and when you're taking your medication, since timing and consistency matter a lot for accurate results. Simple lifestyle steps like avoiding alcohol and staying consistent with meals can help support healthy processing of the drug. If your result is significantly abnormal or you're feeling unwell, seek medical care promptly.

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.

Isoniazid Level Test - TB Medication 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]