What's this test for?

This test is ideal if you're experiencing unexplained blood clots, unusual bleeding, or a prolonged clotting time on previous lab work. It helps figure out if an antibody against Factor XII (a clotting protein) is interfering with your blood's normal ability to clot. It's often used when doctors need more information after an abnormal clotting test, such as an unexpectedly long PTT result.

How should I prepare for this test?

See the pre-collection instructions on your order confirmation.

What's included in this test?

This panel measures Factor XII inhibitor activity, which helps explain why a clotting test might look abnormal even when there's no obvious bleeding or clotting problem. Checking for this specific inhibitor helps rule out a lab artifact versus a true clotting risk, giving a clearer picture of your clotting system's health.

What happens after I get my results?

Your results will show up in your account with a clear explanation of the normal range for Factor XII inhibitor levels. If your results are outside the normal range, the report will explain what that may mean and suggest reasonable next steps, such as repeat testing or additional clotting studies. You can download a standard lab report anytime from your account, and if you test again in the future, the trends feature lets you compare results side by side to see how things change over time.

When will I get my results?

Results are typically ready within about 7 days of your blood draw. This timeframe allows the lab to run the specialized testing needed to accurately measure Factor XII inhibitor activity. You'll get a notification as soon as your results are available in your account.

Who should consider this test?

This test is a good fit for people who've had a prolonged PTT (a common clotting screening test) on previous labwork without a clear explanation. It's also useful for those with a history of unexplained blood clots or bleeding episodes who want more clarity before making health decisions. If a family member has had similar clotting issues, this test can help you understand your own risk.

What symptoms indicate I may need this test?

Signs that may point to a need for this test include unexplained bruising, prolonged bleeding after cuts or dental work, or unexpected blood clots in your legs or lungs. Some people have no symptoms at all and only discover an issue after a routine clotting test comes back abnormal. If you've had unusual results on a PTT test before, this panel can help explain why.

What is Factor XII and why does it matter?

Factor XII is a protein in your blood that helps kick off the clotting process when you get injured. Even though very low Factor XII rarely causes bleeding problems on its own, having an inhibitor (antibody) against it can throw off certain lab tests and occasionally relate to clotting risk. Understanding your Factor XII inhibitor status helps make sense of confusing or abnormal clotting test results.

How often should I retest?

If your first result is abnormal, retesting after a few weeks to a couple of months can help confirm whether the finding is persistent or temporary. For those without ongoing symptoms, retesting isn't usually needed unless new symptoms develop or a doctor orders repeat clotting studies. Tracking results over time in your account can help you and any future testing spot meaningful patterns.

What should I do if my results are abnormal?

If your Factor XII inhibitor level is outside the normal range, it doesn't necessarily mean you have a bleeding or clotting disorder — it often just means further testing is needed to clarify the picture. Keep a record of any symptoms like unusual bruising, bleeding, or swelling, and consider repeat testing to confirm the result. If you notice sudden, severe symptoms like significant swelling, chest pain, or difficulty breathing, seek medical care right away.

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.

Factor XII Inhibitor Panel - Clotting Test Explained

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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