Phospholipids are lipid molecule type which forms a major part of cell membrane. They are crucial for cell’s ability to function and play role in blood clotting. Antiphospholipid antibodies (APA) are mistakenly produced as an autoimmune response against phospholipids. When they are produced, they bind with phospholipids, interfere with clotting process, and increase risk of developing recurrent inappropriate blood clots in veins and arteries. This laboratory test detects antiphospholipid IgG antibodies in blood.
Why is antiphospholipid IgG lab test done?
There are some important phospholipid antibodies for which various tests are done i.e. anticardiolipin, anti-beta2 glycoprotein 1 & lupus antibodies. These tests are done:
To determine cause of inappropriate blood clot formation due to excessive clotting or unexplained thrombotic episode
To determine cause of recurrent miscarriages
To determine cause of thrombocytopenia (low platelet count)
Also, for cause of prolonged PTT test
In diagnosis/or evaluate person with autoimmune disorder
As per the patient’s signs and symptoms & medical history, doctor orders one or more above mentioned test for APA. However, cardiolipin antibodies are most ordered which looks for IgG, IgM & sometimes IgA (immunoglobulin G,M, and A). IgG antibody though appears after several weeks of illness or disease condition, but it provides life-long immunity against the condition.
Firstly, a blood sample is taken by inserting needle in vein in arm
The sample collected in air-tight vial or test tube is sent to the laboratory
The technician performs APA-IgG test by technique called ELISA (enzyme-linked immunosorbent assay) on blood sample. And looks for IgG which is anticardiolipin antibody mostly associated with APA complications.
What is meant by positive antiphospholipid antibody?
It means that patient is suffering from APS (antiphospholipid syndrome). It causes dangerous blood clots in kidneys, lungs, legs & brain
How long will it take before I get my APA lab results?
You get results in 24 to 36 hours. But doctor is unable to predict when a clot might happen, therefore, a second test is ordered after 12 weeks to confirm the results
What is meant by positive anticardiolipin?
Anticardiolipin antibodies has been known to be major criteria in diagnosis of APS. It is found in 30% to 40% of SLE patients
How long is life expectancy in APS individual?
In catastrophic APS individuals, the time course can be devastating and leads to morbidity and early death. An estimation of 10 years approx. in 90% to 94% cases is given.
INTERPRETATION OF THE RESULTS:
Anticardiolipin antibodies are mostly found in individuals with APS. Its ranges include:
Negative: <15 GPL : No APA-IgG antibodies were found
Indeterminate: 15−20 GPL
Low-medium positive: >20−80 GPL : indicate some APA-IgG antibodies found, due to recent health problem
Positive: >80 GPL: indicate increased APA-IgG antibodies present and show higher risk of blood clots
(Here, 1 GPL unit = cardiolipin-binding activity of purified IgA anticardiolipin (at 1 U/mL) form an international reference standard).
You get tested if doctor needs to diagnose reason behind recurrent miscarriages, assess or monitor prolonged PTT (partial thromboplastin time) or assess antiphospholipid antibody syndrome (autoimmune disorder where antiphospholipid antibodies attack the proteins that aid in binding of phospholipids to the plasma membrane). And sometimes also to diagnose/evaluate an autoimmune disorder.