Back Blood-tests Explained


Antiphospholipids


At a Glance

Why Get Tested?

To help investigate the presence of blood clots or an unexpectedly prolonged PTT (partial thromboplastin time), especially if you have had recurrent miscarriages; as part of an evaluation for antiphospholipid syndrome (APS); sometimes to help diagnose or evaluate an autoimmune disorder

When to Get Tested?

When you have an unexplained prolonged PTT test; when you have had recurrent unexplained blood clots; when you have had recurrent miscarriages, especially in the second and third trimesters

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Antiphospholipid antibodies are a group of immune proteins (antibodies) that the body mistakenly produces against itself in an autoimmune response to phospholipids. Tests can detect these autoantibodies that bind to phospholipids and, in a way that is not well understood, increase the risk of excessive blood clotting.

Several tests are available, including:

  • Cardiolipin antibodies (anticardiolipin antibodies)
  • Lupus anticoagulant assays, these include activated partial thromboplastin time (aPTT), dRVVT (dilute Russell viper venom time), kaolin (or silica) clotting time, and PTT mixing tests
  • Beta-2 glycoprotein 1 antibodies

Phospholipids are structural components of cell membranes and play a crucial role in blood clotting. Phospholipds are critical to platelet function in addition to various coagulation co-factors. When antiphospholipid antibodies are produced, they interfere with the clotting process. They increase an affected person's risk of developing recurrent inappropriate blood clots (thrombi) in arteries and veins, which can lead to strokes, heart attacks, and/or miscarriages.

Antiphospholipid antibodies are also associated with low platelet counts (thrombocytopenia) and with the risk of recurrent miscarriages (especially in the second and third trimester), premature labor, and pre-eclampsia.

One or more antiphospholipid antibodies have been identified in various conditions. Some examples are:

Autoimmune disorders

  • Lupus
  • Rheumatoid arthritis
  • Systemic sclerosis

Infections

  • HIV
  • Mononucleosis
  • Rubella

Cancers

  • Solid tumors (colon, lung, etc.)
  • Leukemias
  • Lymphomas

Use of certain drugs

  • Procainamide
  • Phenothiazines
  • Oral contraceptives

The presence of phospholipid antibodies in some instances may be temporary and they have been identified in some individuals who have no detectable illnesses.

Antiphospholipid syndrome (APS), also called Hughes syndrome, is a recognized group of signs and symptoms that includes the formation of blood clots, miscarriages, platelet deficiency (thrombocytopenia), and the presence of one or more antiphospholipid antibodies. APS can be primary with no underlying autoimmune disorder or secondary, existing with a diagnosed autoimmune disorder.

The 14th International Congress on Antiphospholipid Antibodies Task Force criteria for identifying APS requires testing for cardiolipin antibodies, lupus anticoagulant, and beta-2 glycoprotein antibodies when one of two clinical problems exist, blood clots (thrombosis) or pregnancy morbidity.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test



Disclaimer:

MedSquirrel is a shared knowledge, collective intelligence digital platform developed to share medical knowledge between doctors and patients. If you are a healthcare practitioner, we invite you to criticise, contribute or help improve our content. We support collaboration among all members of the healthcare profession since we strive for the provision of world-class, peer-reviewed, accurate and transparent medical information.

MedSquirrel should not be used for diagnosis, treatment or prescription. Always refer any questions about diagnosis, treatment or prescription to your Doctor.