What's this test for?

This test is ideal if you're experiencing unexplained blood clots, a family history of clotting disorders, or recurrent miscarriages. It checks whether your blood has a natural substance called Protein S, which helps keep your blood from clotting too much. Low levels of Protein S can raise your risk of dangerous clots in your legs, lungs, or elsewhere.

How should I prepare for this test?

See the pre-collection instructions on your order confirmation.

What's included in this test?

This test looks at Protein S activity first, since that tells you how well this clotting-control protein is actually working in your body. If activity is low, the test automatically checks total and free Protein S antigen levels, which helps pinpoint whether the issue is a shortage of the protein itself or a problem with how it functions.

What happens after I get my results?

Your results will show up in your account with each value explained alongside its normal range, so you can see exactly where you stand. If your Protein S levels are low, next steps often include retesting to confirm the result and watching for symptoms like leg swelling, pain, or shortness of breath, which need urgent attention. You can download a standard lab report straight from your account at any time, and use the trends feature to track your levels if you test again in the future.

When will I get my results?

Results are typically ready within about 7 days of your blood draw. This slightly longer turnaround is because the test involves a reflex step, meaning the lab may run additional related measurements automatically if your initial result comes back low. You'll get a notification as soon as your results are posted to your account.

Who should consider this test?

This test is a good fit for anyone who has had an unexplained blood clot, especially at a young age, or who has close relatives with a known clotting disorder. It's also useful for people who've had multiple unexplained miscarriages or unusual clotting during pregnancy. If you're starting hormone therapy or birth control and have a family history of clots, this can help you understand your baseline risk.

What symptoms indicate I may need this test?

Watch for symptoms like swelling, warmth, or pain in one leg, which can signal a blood clot. Sudden shortness of breath, chest pain, or coughing up blood can mean a clot has traveled to your lungs and needs emergency care right away. Recurrent pregnancy loss or clotting that runs in your family are also strong reasons to get checked.

How can I naturally support healthy blood clotting balance?

Staying active and avoiding long periods of sitting helps keep your blood circulating well, especially on long flights or car rides. Drinking enough water, maintaining a healthy weight, and not smoking all support normal blood flow and reduce clotting risk. Eating a balanced diet with plenty of vegetables and healthy fats can also support overall vascular health.

What does low Protein S mean?

Low Protein S means your blood may not be able to control clotting as well as it should, which raises your risk of forming clots in your veins. This can be something you're born with (inherited) or something that develops from conditions like liver disease, pregnancy, or certain medications. If your level comes back low, retesting is often recommended to confirm it before drawing conclusions, since some things like pregnancy or blood thinners can temporarily lower results.

How often should I retest?

If your first result is low, retesting a few months later is a common next step to confirm whether it's a lasting pattern or a temporary dip. Once you have a confirmed baseline, retesting isn't usually needed unless you have new symptoms, start a new medication, or become pregnant. Tracking your results over time in your account can help you and any future testing decisions stay organized.

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.

Protein S Activity Test - Blood Clot Risk 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

[email protected]