What is Lupus Anticoagulant Test?

The Lupus Anticoagulant Test is a specialized blood test that detects certain antibodies known to increase the risk of blood clots. Despite the name, this test does not diagnose lupus. Instead, it helps identify antibodies that interfere with the body’s natural clotting system.

These antibodies, often found in autoimmune conditions like Antiphospholipid Syndrome (APS), can sometimes exist in people without any clear symptoms. Doctors may request this test as part of an antiphospholipid antibody panel or a coagulation profile when they suspect abnormal clotting behavior.

Doctors typically recommend the Lupus Anticoagulant Test when:

• You have unexplained blood clots (like deep vein thrombosis or stroke)
• You've had multiple miscarriages, especially in the second or third trimester
• Your PTT (Partial Thromboplastin Time) test results are prolonged
• You're being evaluated for or already diagnosed with APS or SLE (Systemic Lupus Erythematosus)

It helps determine whether the immune system is producing antibodies that could trigger abnormal clotting.

The test may be advised for:

• Individuals with recurrent thrombosis without a clear cause
• Women with repeated pregnancy loss
• People with long clotting times on routine tests like APTT
• Patients already diagnosed with SLE or APS, to monitor their antibody levels

This testing is also common in younger patients who present with stroke or clotting issues, where the underlying cause isn’t obvious.

The Lupus Anticoagulant Test doesn’t measure lupus itself—it checks for the presence of specific antibodies that affect clotting:

• Antibodies: Detects lupus anticoagulants in your blood
• Clotting Time: Evaluates how long your blood takes to form a clot
• dRVVT (Dilute Russell’s Viper Venom Time): A test sensitive to these antibodies
• aPTT (Activated Partial Thromboplastin Time): Another clotting test, often prolonged when these antibodies are present

Each of these helps doctors confirm whether your blood has developed a tendency to clot more easily than it should.

The process is simple:

• A blood sample is collected from your arm
• The sample is sent to a lab for analysis
• Tests like dRVVT, aPTT, and SCT (Silica Clotting Time) are performed
• If necessary, confirmatory tests are used to validate the results

These tests assess whether the antibodies in your blood are slowing down or altering clot formation in specific ways.

Getting ready for a Lupus Anticoagulant test is simple, but there are a few things to keep in mind.

Always let your doctor know about any medicines that you're taking, especially blood thinners like warfarin, heparin, or aspirin, as these can affect the results. You may be advised to pause certain medications temporarily, but only do so under medical guidance.

There’s usually no need to fast or make any major changes to your routine. Your doctor will give you specific instructions if anything extra is needed based on your health condition.

The test itself is quick and straightforward. A nurse or lab technician will clean your arm, insert a small needle into a vein, and collect a blood sample. You might feel a light sting for a second, but the process is generally painless.

The sample is sent to a lab, where it's analysed using specialised tests like aPTT, dRVVT, LA-PTT, or SCT—all of which help detect abnormal clotting behaviour. Results are usually ready in a few days, and your doctor will walk you through what they mean and the next steps, if any.

There’s no single number for a "normal" lupus anticoagulant level, but doctors usually look at specific clotting time measurements:

• PTT-LA (Partial Thromboplastin Time – Lupus Anticoagulant): ≤ 40 seconds
• dRVVT Ratio (Dilute Russell’s Viper Venom Time): ≤ 1.2

If your values are above these limits, it may indicate the presence of lupus anticoagulants in your blood, which could increase your risk for clot-related conditions.

Abnormal lupus anticoagulant levels can occur for several reasons:

• Autoimmune disorders, such as Systemic Lupus Erythematosus (SLE) or Antiphospholipid Syndrome (APS)
• Certain infections like HIV or hepatitis C
• Some medications, especially those affecting the immune system
• Pregnancy complications, like preeclampsia or recurrent miscarriage
• Cancers, particularly of the blood (e.g., lymphoma)

Not everyone with these antibodies will develop symptoms, but knowing about them helps your doctor take preventive steps.

There’s no guaranteed way to prevent lupus anticoagulant antibodies, but you can support your immune system and overall health through:

• A balanced diet rich in antioxidants and anti-inflammatory foods
• Regular exercise, tailored to your ability and energy levels
• Staying hydrated and avoiding alcohol or smoking
• Managing stress, which is known to affect immune responses
• Keeping up with routine check-ups and lab tests

If you're at risk or have been diagnosed with an autoimmune condition, following your doctor's advice closely is key to preventing complications.

After your blood draw, you can usually resume normal activities right away. If you notice any unusual bruising or bleeding, inform your doctor.

If your results show high levels of lupus anticoagulants, your doctor may recommend further testing, lifestyle changes, or medication to reduce clotting risks.

• Don’t stop any medicines on your own—always consult your healthcare provider first
• Keep a personal record of your lab results to track trends over time
• Stay proactive: if you experience any symptoms like leg pain, swelling, or shortness of breath, seek medical attention immediately
• Priorities sleep, good nutrition, and manageable activity levels to support your body’s balance

Content Created By: Priyanka Nishad, Content Writer