APA or Phospholipids Antibodies is a unique ELISA-based test. It is applied to determine the inappropriate blood clot formation. The test is known to successfully ascertain various signs and symptoms of the issue. It can be pain and swelling of the extremities, shortness of breath, and headaches etc. Sometimes this test is used to check the woman who has suffered a miscarriage. This test is applied when the presence of antiphospholipid syndrome is found. It can be a single-use test or multiple times done the test. It is of recurring nature sometimes. The positive reports lead to multiple tests.