1. Window Period: There is a time lag between infection and antibody production, which can delay diagnosis. 2. Cross-Reactivity: Antibodies against one pathogen might react with antigens of another, leading to false positives. 3. Variable Antibody Levels: Factors like age, nutritional status, and immune system function can affect antibody levels, impacting test accuracy. 4. Not Always Indicative of Active Infection: The presence of antibodies does not always mean an active infection; it could indicate past exposure or vaccination.
