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 test for
lupus, a specific type of an 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 in various parts of your
body such as your heart, brain, lungs, and legs. .
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 may need 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:
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?
Test results may vary depending on your age, gender, health history, the method used
for the test, and other things. Your test results may not mean you have a problem.
Ask your healthcare provider what your test results mean for you.
The test results will show whether lupus anticoagulant antibodies are present in the
blood. If your test shows they are, the test should be repeated in several weeks to
If you have lupus or another autoimmune disease, and the test results are negative,
your healthcare provider may want to repeat the test at a later date to determine
if the anticoagulant antibodies have begun to develop.
How is this test done?
The test is done with a blood sample. A needle is used to draw blood from a vein in
your arm or hand.
Does this test pose any risks?
Having a blood test with a needle carries some risks. These include bleeding, infection,
bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may
feel a slight sting or pain. Afterward, the site may be sore.
What might affect my test results?
Your blood sample should be collected before you begin taking anticoagulation medicines,
because they can alter the results.
Tell your healthcare provider if you are taking any other medicines because they might
interfere with your test results. Infection or cancer, can also 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 don't need to prepare for this test. Be sure your healthcare provider knows about
all medicines, herbs, vitamins, and supplements you take. This includes medicines
that don't need a prescription and any illegal drugs you may use.