Autoantibody Testing

Antibody testing.

• To help diagnose autoimmune disorders by detecting and measuring the levels of autoantibodies.
• To monitor the course of an autoimmune disorder.

The presence of autoantibodies, detected by immunofluorescence or ELISA methods, means the body is making antibodies that are fighting its own tissue.

None.

A sample of your blood is drawn and analyzed for the presence of particular antibodies.

Follow procedure for drawing blood.

• Drugs such as alphamethyldopa, chlorpromazine, diphenyl hydantoin, hydralazine, isoniazid, procainamide, and quinidine (even several months after they are stopped) may trigger production of antinuclear antibodies (ANAs) and produce false-positive results.
• Other drugs may lead to the production of other antibodies.
• ANAs may be found in the blood of healthy people aged 60 or older or occasionally in some younger people.

This test may detect the following antibodies:

• Antinuclear antibody (ANA), which may be present in autoimmune disorders, particularly lupus, scleroderma, Sjögren's syndrome, polymyositis, and certain types of chronic active hepatitis.
• Anti-DNA antibody, which may be present in lupus but is usually not found in other autoimmune diseases. Levels generally decrease when treatment of lupus is successful.
• Antiphospholipid antibody, which may be found in lupus and certain other conditions. Associated with clots and miscarriages.
• Anti-smooth muscle antibody, which may be present in chronic active hepatitis. Testing helps distinguish between this type of hepatitis and other forms of liver disease.
• Antimitochondrial antibody, which is present in most cases of primary biliary cirrhosis and (rarely) with other types of chronic liver disease.
• Rheumatoid factor, which is often found in the blood and joint fluids of people with rheumatoid arthritis.

There's no risk.

• Presence of antibodies does not lead to a definitive diagnosis, while absence does not always rule out a disease.
• Levels of antibodies do not always correspond to severity of disease.
• Test sometimes produces false-positive and false-negative results.

• If antibodies are present along with appropriate symptoms, they are indicative of an autoimmune disorder, and treatment may be initiated.
• Absence of antibodies suggests a condition other than an autoimmune disorder; other tests may be ordered.