In leptospira serology testing, which error is more common?

• A. False negatives
• B. False positives
• C. Both equally common
• D. No errors occur

Answer: (A)

Antibody-based serology hinges on the timing of the patient’s immune response. In leptospira infection, antibodies often aren’t detectable in the first days of illness, so an initial serology can be negative even when infection is present. This window period makes false negatives more common than false positives. Sensitivity can also be limited if the infecting serovar isn’t represented in the test panel, but the biggest factor early on is lack of detectable antibodies. To improve accuracy, clinicians rely on paired sera to look for seroconversion or a rise in titer, or use molecular tests like PCR in the acute phase.