Does this test have other names?
LA, Lupus Anticoagulant Panel, Lupus Inhibitor, LA Sensitive PTT, PTT-LA, Dilute Russell
Viper Venom Test, DRVVT, Modified Russell Viper Venom Test, MRVVT
What is this test?
This is a special blood test to find out if your body is making certain antibodies
or proteins that cause you to have a blood-clotting disorder. It does not mean you
have lupus, specific type of autoimmune disorder.
Antibodies are proteins in the blood that help you fight off foreign invaders such
as viruses and bacteria. Lupus antibodies are one of two types of antiphospholipid
antibodies that are sometimes found in blood. Antiphospholipid antibodies are proteins
that react to the phospholipids, or fat molecules, normally found in the membranes
of blood cells. Antiphospholipids can interfere with the work of your blood cells.
They can cause blood vessels to narrow and clots to form. Clots can lead to heart
attacks, strokes, pulmonary embolisms, and deep vein thromboses. These occur when
blood clots form in the deep veins of the body.
These antibodies are called lupus antibodies because they were first discovered to
be related to lupus. But not everyone who has lupus has these antibodies. And people
who don't have lupus can start making them. The reason is unknown.
Why do I need this test?
You might have this test if you get blood clots that can't be explained. You may also
have this test if you have repeated miscarriages, or you have other blood tests that
show your blood takes a long time to clot. You might be asked to take this test again
if the lupus anticoagulant is found in your blood. Taking the test again will help
your healthcare provider find out if the condition is temporary or persistent.
What other tests might I have along with this test?
If your test results are positive, your healthcare provider is likely to order other
special blood-clotting tests. They might include:
Repeating the test
Activated partial thromboplastin time
Modified Russell viper venom time, or MRVVT
Platelet neutralization procedure, or PNP
Kaolin clotting time, or KCT
Coagulation factor assays
Complete blood cell count, or CBC
What do my test results mean?
A result for a lab test may be affected by many things, including the method the laboratory
uses to do the test. If your test results are different from the normal value, you
may not have a problem. To learn what the results mean for you, talk with your healthcare
The test results will show whether lupus anticoagulant antibodies are present in the
blood. If your test shows they are, it should be repeated in several weeks to confirm.
Normal values range from 20 to 39 GPL or MPL units.
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection,
bruising, and a sense of lightheadedness. When the needle pricks your arm, you may
feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
Your blood sample should be collected before you begin taking anticoagulation medicines,
because they can skew the results.
Tell your healthcare provider if you are taking any other medicines because they might
interfere with your test results. If you have an infection or cancer, it can affect
your test results.
If the lab where the LA test is done is inexperienced with the test, it could result
in false positives.
How do I get ready for this test?
You do not need to prepare for this test.