Systemic Lupus Erythematosus
Symptoms of Lupus continued...
Diagnosing lupus can be difficult. It may take months or even years for
doctors to piece together the symptoms to diagnose this complex disease
accurately. Making a correct diagnosis of lupus requires knowledge and
awareness on the part of the doctor and good communication on the part of the
patient. Giving the doctor a complete, accurate medical history (for example,
what health problems you have had and for how long) is critical to the process
of diagnosis. This information, along with a physical examination and the
results of laboratory tests, helps the doctor consider other diseases that may
mimic lupus, or determine if the patient truly has the disease. Reaching a
diagnosis may take time as new symptoms appear.
No single test can determine whether a person has lupus, but several
laboratory tests may help the doctor to make a diagnosis. The most useful tests
identify certain autoantibodies often present in the blood of people with
lupus. For example, the antinuclear antibody (ANA) test is commonly used to
look for autoantibodies that react against components of the nucleus, or
"command center," of the body's cells. Most people with lupus test
positive for ANA; however, there are a number of other causes of a positive ANA
besides lupus, including infections, other autoimmune diseases, and
occasionally as a finding in healthy people. The ANA test simply provides
another clue for the doctor to consider in making a diagnosis. In addition,
there are blood tests for individual types of autoantibodies that are more
specific to people with lupus, although not all people with lupus test positive
for these and not all people with these antibodies have lupus. These antibodies
include anti-DNA, anti-Sm, anti-RNP, anti-Ro (SSA), and anti-La (SSB). The
doctor may use these antibody tests to help make a diagnosis of lupus.
It may take months or even years for doctors to piece together the symptoms
to accurately diagnose this complex disease.
Some tests are used less frequently but may be helpful if the cause of a
person's symptoms remains unclear. The doctor may order a biopsy of the skin or
kidneys if those body systems are affected. Some doctors may order a test for
anticardiolipin (or antiphospholipid) antibody. The presence of this antibody
may indicate increased risk for blood clotting and increased risk for
miscarriage in pregnant women with lupus. Again, all these tests merely serve
as tools to give the doctor clues and information in making a diagnosis. The
doctor will look at the entire picture-medical history, symptoms, and test
results-to determine if a person has lupus.