What are the other Names for this Test? (Equivalent Terms)
- Dilute Russell Viper Venom Blood Test (DRVVT)
- LA Sensitive PTT Blood Test
- Lupus Anticoagulant Antibodies Blood Test
What is Lupus Anticoagulant Blood Test? (Background Information)
- Lupus anticoagulants (LAs) are autoantibodies that increase the blood’s tendency to clot. This may cause thrombosis or blood clotting within the vessels
- Antibodies are bodily defense proteins made by cells of the immune system. They deactivate foreign microbes and toxins by binding to them and help in clearing them from the body
- Autoantibodies target host cells instead of foreign invaders. They cause autoimmune diseases. LAs are autoantibodies that target the body’s own platelets
- Platelets play a crucial role in blood clotting. They release factors essential to the regulation of the clotting process. In addition, platelets form the material for a clot
- Normally, platelets do not form a clot unless they are activated at the site of a blood vessel injury. However, platelets bound by LA stick more readily to the blood vessel lining and pile up. This increases the risk of thrombosis
- Thrombosis may result in impaired blood flow to the organs or a total lack of blood flow. They are also dangerous because they may dislodge to form a traveling mass called an embolus, which may clog distant blood vessels
- Lupus Anticoagulant Blood Testing involves several tests that detect the presence of lupus anticoagulants. It is used to assess the risk of thrombosis and to guide treatment
What are the Clinical Indications for performing the Lupus Anticoagulant Blood Test?
Following are the clinical indications for performing a Lupus Anticoagulant Blood Test:
- Following up to a prolonged partial thromboplastin time (PTT) test
- Pain, swelling, discoloration, and tenderness of the extremities, especially the legs
- Unexplained miscarriage or infant death
- Rapid breathing
- Rapid heart rate
- Discoloration of the fingers, especially in cold temperatures (Raynaud’s phenomenon)
How is the Specimen Collected for Lupus Anticoagulant Blood Test?
Following is the specimen collection process for Lupus Anticoagulant Blood Test:
Sample required: Blood
Process of obtaining blood sample in adults:
- A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
- The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
- The needle cap is removed and is held in line with the vein, pulling the skin tight
- With a small and quick thrust, the vein is penetrated using the needle
- The required amount of blood sample is collected by pulling the plunger of the syringe out slowly
- The wrap band is removed, gauze is placed on the collection site, and the needle is removed
- The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
- The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the Lupus Anticoagulant Blood Test Result?
- A positive result may indicate an increased susceptibility to thrombosis or thrombosis caused by lupus anticoagulants
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results based on the overall clinical scenario.
Additional and Relevant Useful Information:
- It should be emphasized that the name lupus anticoagulant (LA) is inaccurate and causes tremendous confusion. But, for historic reasons, it is still retained.
- The lupus anticoagulant antibodies can also be found in patients, who do not have lupus. LAs were first discovered in individuals with lupus, and they are anticoagulants in a test-tube
- The Lupus Anticoagulant Test is often performed alongside coagulation factor assays and a complete blood count
- Certain factors interfere with the results of this test. These include rheumatoid arthritis and systemic lupus erythematosus
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider of the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.