What's this test for?

This test is ideal if you're experiencing unexplained bleeding or bruising, or if you have a family history of hemophilia B and want to understand your clotting protein levels. It's also useful if you're already diagnosed with factor IX deficiency and need a closer look at how much of the clotting protein your body actually makes, separate from how well that protein works. Many people use it to check carrier status or to follow up on gene therapy or factor concentrate treatment.

What's included in this test?

This test measures the actual amount of factor IX protein circulating in your blood, using an antibody-based method called ELISA. Looking at the antigen level alongside a functional activity test helps distinguish between having too little of the protein versus having enough protein that just isn't working properly, which matters for diagnosis and treatment planning.

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 factor IX antigen level is outside the expected range, simple next steps include discussing timing of any bleeding episodes, avoiding blood-thinning medications like aspirin without guidance, and considering a repeat test to confirm the finding. 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 your levels change over time.

How should I naturally support healthy clotting?

Eating foods rich in vitamin K, like leafy greens, supports normal clotting factor production, and staying well hydrated helps blood flow smoothly. Avoiding excess alcohol and unnecessary use of blood-thinning supplements like fish oil or high-dose vitamin E can also help maintain steady clotting function. That said, genetic clotting factor deficiencies like hemophilia B aren't reversed by diet alone, so any bleeding symptoms should be taken seriously and monitored closely.

When will I get my results?

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

Who should consider this test?

This test is a good fit for people with a personal or family history of hemophilia B, women who may be carriers of the condition, and anyone already being treated with factor IX concentrates or gene therapy who needs to track protein levels. It's also useful for anyone whose functional clotting test came back low and needs more detail on what's driving that result.

What symptoms indicate I may need this test?

Frequent or unexplained bruising, prolonged bleeding after minor cuts or dental work, heavy or prolonged menstrual periods, and joint swelling or pain without injury can all be signs of a clotting factor issue. A family history of hemophilia B is also a strong reason to consider testing even without symptoms.

What does a low factor IX antigen level mean?

A low level means your body isn't producing enough of the factor IX protein, which is one of the proteins your blood needs to form clots properly. This is the hallmark of classic hemophilia B, and the severity of bleeding symptoms usually tracks with how low the level is. Confirming this with a repeat test and a functional activity test helps clarify the full picture.

What causes an abnormal factor IX antigen result?

The most common cause is an inherited genetic mutation affecting the factor IX gene, which runs in families and is passed down in a specific pattern. Liver disease can also lower factor IX levels since the liver produces this protein, and certain medications or vitamin K deficiency can interfere with normal levels too. In rare cases, an antigen level that's near normal but paired with low functional activity points to a variant where the protein is present but not working correctly.

How often should I retest?

If you're being monitored for an existing diagnosis or ongoing treatment like factor concentrates or gene therapy, retesting every few months or as advised on your treatment plan is common. If this is a one-time screening test with a normal result and no symptoms, you likely won't need to repeat it unless new symptoms appear.

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 IX Antigen Test - Hemophilia B Screening

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]