Lupus Anticoagulant

Lupus anticoagulant (LA) is an antibody your immune mistakenly produces. Its name is confusing because it’s not always related to having lupus, and it isn’t an anticoagulant. In fact, having LA in your blood can increase your risk of blood clots. It can cause antiphospholipid syndrome, an autoimmune disease.


What is lupus anticoagulant?

Lupus anticoagulant (LA) is a type of antibody.

Usually, your immune system makes antibodies to protect you. They’re special proteins that act like an army of security robots that find and destroy germs, allergens or toxins in your blood. When your immune system detects a new unwanted substance in your body, it makes antibodies customized to find and destroy that invader. But sometimes, your immune system makes antibodies that harm your body instead of protecting it. Lupus anticoagulant is one type of harmful antibody.

Lupus anticoagulant is one of three malfunctioning antibodies called antiphospholipid antibodies. These antibodies can cause antiphospholipid syndrome (APS). APS is an autoimmune disease that makes your body much more likely than usual to form blood clots.

What is a positive lupus anticoagulant test?

Being positive for lupus anticoagulant means a healthcare provider found the antibody in a sample of your blood. A healthcare provider will use blood tests to check for signs of lupus anticoagulant if they think you might have APS. Most people aren’t screened for APS until after they’ve experienced an unusual blood clot or pregnancy complication.

Does having lupus anticoagulant mean I have lupus?

Lupus anticoagulant’s name is confusing. Decades ago, researchers discovered LA in blood samples from people who had lupus. They noticed that blood samples with LA seemed to clot more slowly than usual. That’s why they named LA the way they did: an antibody (they thought) only people with lupus had that prevented clotting (anticoagulation). The problem is that neither of those guesses were correct.

Even though some people with lupus do have LA in their blood, your immune system can make it even if you don’t have lupus. It’s also not an anticoagulant. In fact, it’s the exact opposite — having lupus anticoagulant increases your risk of APS, which makes your blood clot more often than it should.

The shortest answer is that having LA in your blood doesn’t necessarily mean you have lupus. But lots of people with autoimmune diseases (including lupus) have LA. These tiny, super-specific details can be confusing. Your healthcare provider will help you understand your blood test results and what they mean for your health.


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Possible Causes

What causes lupus anticoagulant?

Your immune system produces lupus anticoagulant by mistake. Antiphospholipid antibodies attack healthy cells in your body instead of protecting you from a harmful invader.

Antiphospholipid antibodies get their name from how they damage your cells. They attack proteins bound to phospholipids (a type of fat cell). These attacks damage the phospholipids, making them more likely to clump together and form blood clots.

Even though experts know LA and other antiphospholipid antibodies cause antiphospholipid syndrome, they aren’t sure what triggers your immune system to start making them.

Care and Treatment

What does it mean if you have lupus anticoagulant?

Having lupus anticoagulant in your blood is a risk factor for developing antiphospholipid syndrome. That’s why some healthcare providers call APS lupus anticoagulant syndrome.

People who have APS have at least one of the antibodies that cause it. However, it’s possible to have LA in your blood and never have a blood clot, experience a pregnancy complication or develop APS. It’s just a risk factor that means you’re more likely than most people to have these issues.

What are lupus anticoagulant treatments?

Your provider will suggest treatments that manage how much LA affects you, but there aren’t any treatments that can make it go away. For example, you might need blood thinners or corticosteroids to manage antiphospholipid syndrome.

Immunosuppressants can reduce how overly active your immune system is, but no treatment can tell your immune system to stop producing LA once it starts.


When To Call the Doctor

When should I see my healthcare provider?

Your provider will tell you how often you’ll need checkups to monitor changes in your body and blood and to screen you for antiphospholipid syndrome.

If you’re taking blood-thinners, you’ll need to see your provider regularly to make sure your blood is still able to clot safely if you get a cut or bruise.

When should I go to the emergency room?

Go to the ER right away if you:

  • Think you have a blood clot.
  • Experience any symptoms of a clot.
  • Are bleeding and can’t control it.

Additional Common Questions

Does lupus anticoagulant make you tired?

Lupus anticoagulant doesn’t cause any symptoms, but fatigue (feeling tired all the time) is a common autoimmune disease symptom. So, even if LA isn’t directly making you tired, having an autoimmune condition might be. Talk to your provider if you’re feeling tired or like you don’t have the same amount of energy. They’ll help you find ways to manage the tiredness, no matter what’s causing it.


What is the survival rate for lupus anticoagulant?

Having lupus anticoagulant in your blood isn’t fatal itself. But antiphospholipid syndrome can cause life-threatening complications if you experience a blood clot that blocks a blood vessel in one of your organs.

A note from Cleveland Clinic

Lupus anticoagulant is a small, silent antibody that many people don’t even know they have until they experience a blood clot and get diagnosed with antiphospholipid syndrome. Having LA in your blood doesn’t mean you’ll experience severe complications, but your risk will be higher than most people’s.

It’s frightening to think that there’s something in your body you can’t see or feel that might hurt you. It’s normal and completely healthy to feel scared, upset or worried. You might need to be on the lookout for blood clot warning signs, but you don’t have to live in fear. Talk to your healthcare provider. They’ll explain what to watch out for and how to reduce your clot risk.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 04/04/2024.

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