What's this test for?

This test is ideal if you're taking ustekinumab (Stelara) for psoriasis, Crohn's disease, or ulcerative colitis and your symptoms have started coming back or the medication doesn't seem to be working as well as before. It checks whether your body has started producing antibodies against the drug, which can make it less effective. This is useful if you and your care plan are trying to figure out why a treatment that used to work well has stopped controlling your flare-ups.

What's included in this test?

This is a single, targeted lab measurement rather than a multi-marker panel, so there isn't a list of different biomarkers involved. It specifically measures antibodies your immune system may have created against the drug ustekinumab. This single number helps explain whether reduced drug effectiveness is related to your immune system fighting the medication itself.

What happens after I get my results?

Your results will be available in your account, with the normal reference range explained so you know exactly what your number means. If your antibody level is above 2 AU/mL, that's a sign anti-drug antibodies are present, which is worth noting alongside how well your symptoms are currently controlled. The standard lab report is downloadable from your account any time, and you can track this value over time using the trends feature if you retest in the future. If your symptoms are worsening significantly, consider seeking prompt medical care rather than waiting for a scheduled retest.

Who should consider this test?

Anyone currently on ustekinumab therapy for psoriasis, Crohn's disease, or ulcerative colitis who notices their symptoms returning despite staying on treatment should consider this test. It's also useful if drug levels seem lower than expected on related testing. People who have been stable on ustekinumab for a long time generally don't need this test unless something changes.

When will I get my results?

Results are typically ready within about 7 days of your sample being collected at the lab. You'll receive a notification once your results are posted to your account. This turnaround gives enough time for the specialized antibody analysis to be completed accurately.

What symptoms indicate I may need this test?

Watch for returning skin plaques or itching if you're treated for psoriasis, or increased abdominal pain, diarrhea, or rectal bleeding if you're treated for Crohn's disease or ulcerative colitis. Any noticeable loss of symptom control after a period of stability on ustekinumab is a signal worth investigating. Fatigue or new joint pain flaring back up can also be worth flagging.

What is an anti-drug antibody and why does it matter?

An anti-drug antibody is a protein your immune system makes that specifically targets a medication, in this case ustekinumab, treating it like a foreign invader. When these antibodies form, they can neutralize the drug or speed up how quickly your body clears it, leading to lower drug levels and reduced symptom control. Understanding whether antibodies are present helps explain why a previously effective treatment may be losing its impact.

What does a high (positive) antibody result mean?

A result above 2 AU/mL means detectable anti-drug antibodies are present in your blood. This often correlates with lower trough levels of the drug itself, which can reduce how well the medication controls your condition. It doesn't automatically mean the drug has completely stopped working, but it's a meaningful piece of the puzzle if your symptoms are flaring.

What causes anti-drug antibodies to develop?

Your immune system can sometimes recognize a therapeutic antibody like ustekinumab as foreign material and mount a response against it, similar to how it would respond to a virus. This happens in only a small percentage of people on this medication, so most people never develop significant antibody levels. Missing doses or inconsistent dosing schedules may increase the chance of antibody formation in some people.

How often should I retest?

Retesting is generally only needed if your symptoms change or your treatment plan is being reevaluated, rather than on a fixed routine schedule. If your first test comes back negative but symptoms later return, retesting at that point can help clarify what's changed. Tracking results over time in your account can help you and anyone helping manage your treatment spot trends.

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.

Ustekinumab Antibody Test - Biologic Drug Response Check

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

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