Laboratory Tests in Lupus
May 2nd, 2003Special Report Michael D. Lockshin, MD
1. ANA,FANA (Fluorescent)-Anti-Nuclear Antibody 2. Anti-DNA 3. anti-Sm antibody-_Antibody to the Smith antigen 4. anti RNP-Antibody to the Ribonucleoprotein 5. anti-Ro,(=anti-SSA(=anti-Ro)) 6. anti-La,(=anti-SSB) 7. Complement,CH50,C3,C4 8. aCL, aPL, lupus anticoagulant 9. BUN (Blood Urea Nitrogen) 10. Urinary protein, proteinuria, albuminuria 11. Platelets- blood cells that aid in clotting.
Are you confused by the names of the blood tests doctors use to diagnose or monitor lupus? Do you know what the tests mean? If you are confused, perhaps the information below will help. In looking at the following information, remember: An antibody is a protein (such as gamma globulin and other globulins) that the body normally makes to defend itself against bacteria (germs), viruses, and other things that cause harm. In lupus, the body mistakenly makes antibodies against a person's normal tissue. An antibody is named according to the substance (antigen) which it is made to fight. Thus, an antibody induced by a polio vaccination is called anti-polio virus antibody. Because the basic abnormality of lupus is an immune system that is in overdrive, most of the tests measure the degree to which the immune system is active. Other tests measure the function of specific organs such as the kidneys. A lot of these tests and names are confusing. Don't worry about such designations as mg/dL (milligrams per deciliter). These are technical terms that refer to a specific way of measuring one or another substance. Some laboratories use international units (IUs); some laboratories report the results of chemical tests in mols instead of milligrams. I've given the measurements that are most often used. If your laboratory reports your results in a different way, ask your doctor to explain which units are used and what is normal for that laboratory. I have not given numbers for tests that are either reported as positive/negative, or in cases where there are too many ways of reporting to summarize briefly. Keep in mind that the statements above are just rough guides. There are always exceptions to every rule. I've listed the most common tests and the most common uses, but they may differ for you. If you are still confused, or you are in doubt, ask your doctor for an explanation. Test: ANA, FANA (Fluorescent) - Anti-Nuclear Antibody What test is for: An antibody against the nucleus, or central controlling part of each cell. All organs are made of cells and all cells have nuclei. ANAs have four basic patterns describing the way they look under the microscope. The patterns are "diffuse" (the whole nucleus lights up), "peripheral" or "rim" (only the ring around the nucleus does), "speckled" and "nucleolar" (two very specific spots light up). What a positive test means: Almost all patients with lupus have a strongly positive test (still positive even when diluted more than 100 times, commonly expressed 1:100). Many normal people also have positive tests, usually less strong (1:10-1:30). The "diffuse" and "speckled" patterns are common in lupus, but are also seen in other diseases and normal people. The "peripheral" pattern is relatively specific for lupus. The "nucleolar" does not often occur in lupus. A positive test means lupus is a possible diagnosis. What a negative test means: A negative test usually means that a patient does not have lupus, or that lupus is in remission. However, most patients in remission do not have negative ANAs. … See the complete article on the Hospital for Special Surgery’s web site