What does a positive antinuclear antibody (ANA) test indicate?

• A. Bacterial infection
• B. The presence of antibodies against self-DNA and nuclear materials, seen in autoimmune disorders
• C. Liver failure
• D. Acute myocardial infarction

Answer: (B)

A positive ANA indicates antibodies that target components inside the cell’s nucleus, such as DNA and other nuclear materials. This pattern is a hallmark of autoimmune disorders, where the immune system mistakenly attacks the body's own tissues. In practice, a positive ANA often leads to further testing for more specific autoantibodies (like anti-dsDNA or anti-Smith) and to clinical correlation to determine the exact autoimmune condition. It’s important to remember that ANA is a screening finding, not a definitive diagnosis by itself, and it’s not typically associated with bacterial infection, liver failure, or acute myocardial infarction.