The human body has proteins called antibodies which play a key role in the functioning of the immune system. The human body produces natural antibodies when exposed to antigens, like dust, pollen, or bacteria. The B-lymphocytes in the body are responsible for the production of antigens via immunoglobulins. It is also possible to create synthetic antibodies thanks to recombinant antibody biopanning. Five types of antibodies or immunoglobulin isotypes are present in the human body. Each one has different functions and is distributed differently within the body. These are: IgA  IgD IgE IgG IgM Among these, the IgM and IgG isotypes are the most important ones. IgG is the primary antibody in the blood. It is exceedingly efficient in binding toxins and bacteria and is perhaps the most vital antibody in your immune system. The IgM isotypes act as the initial immune system defence of the body. Despite being essential to healthy living, antibodies can sometimes cause problems. Antiphospholipid syndrome (APS) is a condition where the immune system produces excessive antiphospholipid antibodies, causing blood to clot. The condition can worsen in the presence of other autoimmune conditions, e.g., lupus, rheumatoid arthritis, systemic sclerosis, etc. Although symptoms may not always be visible in antiphospholipid syndrome, the blood clots can be dangerous, especially in the following conditions: During pregnancy  Consuming oral contraceptives  Undergoing estrogen therapy  Being immobile due to long flights, complete bed rest, etc.  Cigarette smoking  Surgery  High cholesterol  Increased level of triglycerides  HIV  Tumors in the lung, colon, etc.  Lymphomas  Leukemia The results can be fatal as the disease can cause:  Complications during pregnancy, like pre-eclampsia, miscarriage, or stillbirth  Cardiovascular problems  Lung problems  A stroke  Kidney failure Anti-Phospholipid Antibody IgG and IgM Test or APLA IgM test can help diagnose several complications in this case. Although there is no permanent cure for antiphospholipid syndrome, the patient can have a successful pregnancy. It may not always be possible to detect visible symptoms. Doctors prescribe the antiphospholipid IgG and IgM tests in cases like: Repetitive miscarriages, especially in the 2nd or 3rd trimester Recurring blood clots for no apparent reason  Routine evaluation of the antiphospholipid disorder  Diagnosis of autoimmune disorders  Prolonged PTT test (partial thromboplastin time) It is possible to detect the antiphospholipid antibodies that bind to the blood with the APL IgM test. The ELISA-based screening test requires a blood sample drawn from the veins of your arm. Both the Anti-Phospholipid Antibody IgG and Anti Phospholipid Antibody IgM tests are needed to detect both isotypes. The sample collection process is a simple blood test. It may even be possible to do a "fingerstick" test or heel-stick collection for children. You can get a package covering both the tests from Apollo 24|7. Upon detection of antiphospholipid syndrome, the doctor may ask you to avoid foods rich in Vitamin K, like cabbage, broccoli, and leafy grains. The doctor may even prescribe medications, like aspirin, if you have no previous history of blood clotting but are aPL-positive.    Medically reviewed by Dr. Soumya Bhattacharya, Haematologist, Apollo Multispeciality Hospitals, Kolkata.