Which autoantibody test has replaced the LE cell test and is often positive in autoimmune diseases, with high titers correlating with disease but many false positives?

• A. dsDNA
• B. RF
• C. Anti-CCP
• D. ANA

Answer: (D)

Antinuclear antibody testing serves as the broad screening for autoimmune diseases and has largely replaced the LE cell test. It detects antibodies directed against components of the cell nucleus, so it is highly sensitive—meaning a negative result makes autoimmune disease unlikely, while a positive result is common across many conditions and even in some healthy people, leading to false positives. Because of this, a positive ANA signals autoimmune activity but isn’t disease-specific; it prompts follow-up with more targeted tests to identify the exact disorder. In practice, high ANA titers can correlate with disease activity in certain conditions like SLE, but this relationship isn’t perfect and must be interpreted in the clinical context. The other tests fit narrower roles: dsDNA antibodies are highly specific for SLE and help confirm and monitor it; RF can be positive in various conditions and even in healthy individuals, reducing its diagnostic specificity for rheumatoid arthritis; anti-CCP is highly specific for rheumatoid arthritis and useful for early confirmation. Thus, the ANA stands out as the replacement for LE cells and the most broadly positive test across autoimmune diseases.