Laboratory Diagnosis of Leptospirosis.

Accurate laboratory diagnosis of leptospirosis is essential because the clinical manifestations are nonspecific and overlap with those of many other infectious diseases. The optimal diagnostic approach depends on the stage of illness, with nucleic acid amplification tests (NAATs) being most useful during the acute phase and serological methods becoming more informative after antibody production. This chapter reviews current laboratory diagnostic methods for leptospirosis, including culture, NAATs, serological assays, and antigen detection methods. The advantages and limitations of each approach are discussed, together with recent advances in molecular and serological diagnostics. Appropriate selection and combination of diagnostic methods according to the stage of illness remain essential for accurate diagnosis. Further development of rapid and reliable diagnostic tests suitable for resource-limited settings is still urgently needed.