Antiphospholipid Syndrome Program

About APS

Antiphospholipid syndrome (APS) is a condition that can cause blood clots to form in the body’s blood vessels, which can lead to serious, even life-threatening health problems.

APS is an autoimmune disorder. These disorders cause the body’s immune system — which is there to protect the body from disease and infection — to attack healthy cells by mistake. APS is one of more than 80 known autoimmune disorders that can impact various organs as well as joints, muscles, skin and blood. Other common autoimmune disorders are rheumatoid arthritis and lupus.

In APS, the immune system makes antibodies that mistakenly attack a type of fat molecule called a phospholipid. Phospholipids are found on the surface of many cells throughout the body, including cells in the bloodstream and cells that line blood vessels.

When antibodies attack phospholipids or proteins that bind to them, cells are damaged. This can cause abnormal blood clots to form in the body's blood vessels, which can block blood flow and damage the body's organs.

APS can lead to serious health problems including stroke, heart attack, deep vein thrombosis, pulmonary embolism, and kidney damage. In women it can also cause pregnancy-related problems such as miscarriage or premature birth due to preeclampsia or eclampsia.

Other problems associated with APS include damage to heart valves, low blood counts (especially platelets), cognitive dysfunction (or problems thinking clearly), and a type of skin discoloration called livedo reticularis.

Risk Factors of Antiphospholipid Syndrome

APS can affect people of any sex and can be diagnosed at any age. In general, it seems to affect women more often than men, and is often diagnosed between the ages of 20 and 40.

Genetics likely increase a person’s risk of having APS, although more research is needed to understand which specific genes are associated with that risk.

It is possible for some people to produce antibodies that attack phospholipids, but never develop blood clots. However, for people with these antibodies, a number of factors seem to be linked to an increased risk of developing blood clots, including smoking, high blood pressure, obesity, taking estrogens (birth control pills), extended periods of inactivity such as bed rest, and having an associated autoimmune disease like lupus.

Symptoms of Antiphospholipid Syndrome

The most significant symptom of APS is abnormal blood clotting. Some of the signs of blood clots include:

  • Pain
  • Redness, warmth, and swelling in the limbs
  • Chest pain and shortness of breath
  • Upper body discomfort in the arms, back, neck, and jaw
  • Speech changes

Every patient is different, and symptoms can sometimes be quite subtle, including headaches, changes in thinking, involuntary movements and vision loss. Patients have also been diagnosed after having abnormal lab tests (including tests for blood clotting, blood cell counts, and kidney function).

Diagnosis of Antiphospholipid Syndrome

Diagnosis of APS begins with a review of a patient’s medical history and a series of blood tests that check for the presence of antibodies that attack phospholipids. It is typical to perform these tests at least 12 weeks apart, to measure changes in the antibodies over time.

Treatment of Antiphospholipid Syndrome

When APS is suspected, a patient should be referred to a rheumatologist for further evaluation and treatment. (Note that it is not always necessary to complete all of the blood tests for a doctor to suspect APS and seek a referral).

There is currently no cure for APS. The goal of treatment is to prevent future blood clots from forming and to avoid additional damage to organs.

Blood thinners (anticoagulants) are typically part of the treatment regimen, although these do not prevent all cases of blood clotting in APS. Additional medications and lifestyle changes may also be recommended for some patients.

It’s estimated that 30 to 50 percent of people with APS also have a second autoimmune disease such as lupus. It is important to diagnose and control these conditions as well, in order to improve outcomes related to APS.

Michigan Medicine’s Antiphospholipid Syndrome Program

The Michigan Medicine Antiphospholipid Syndrome Program is home to both clinical and research activities associated with APS. That means that while team members are focused on providing the highest level of care for each patient, they are also dedicated to research to find new and better ways to treat and ultimately cure APS.   

Our approach to treatment recognizes that APS is different in every person. Along with specialists in hematology, obstetrics, neurology, nephrology and more, our rheumatologists work with each patient to develop a personalized treatment approach to pursue the very best possible long-term outcome.

Patients with suspected or confirmed diagnoses of APS are seen in the Adult Rheumatology Clinic.

APS Program Community Q&A Series

The APS Program Community Q&A Series, written by Yu (Ray) Zuo, MD, addresses questions received from the APS Program community and will cover a variety of topics.

About APS Research at Michigan Medicine

Ongoing research at Michigan Medicine seeks to understand why certain people develop APS, to find new and better ways to treat the disease, and ultimately, to find a cure.   

Collaborations with Michigan Medicine researchers in Biomedical Engineering, Cardiovascular Medicine, and Vascular Surgery are taking on APS from all angles, using the latest advances in cell and molecular biology, pharmacology, genetics, and epigenetics.

Projects include pursuing anti-inflammatory treatments that might provide a more targeted approach with fewer side effects. Specifically, investigators are exploring the role that neutrophils, the most abundant white blood cells in the body, play in APS.

In addition, the program collaborates with many national and international partners, providing our patients access to the latest clinical trials and study protocols.

Participate in APS Research

Patients who wish to are given the opportunity to participate in research at every clinic visit, by donating blood for studies into the genetic and cellular causes of APS. These studies would not be possible without samples of blood from people who have antiphospholipid antibodies. By partnering with us in research, patients have a chance to make a positive impact on their own care and the care of future patients around the world.

To learn more about our research, please visit our lab website.

To learn more about current clinical studies, visit our antiphospholipid study page on

Make an Appointment

A doctor’s referral is recommended for new patients. Physicians can connect with the clinic by calling MLine, our 24/7 physician-to-physician portal, at 1-800-962-3555.

We recommend that new patients who are referred by doctors outside of Michigan Medicine bring copies of all laboratory and imaging tests to their first appointment. Access to the latest information allows us to develop a treatment plan as quickly as possible.

Existing patients who have questions about treatment or about scheduling or rescheduling appointments can phone the clinic directly at 1-888-229-3065.