After infection, leptospires are present in the blood until they are cleared after 5 to 10 days after onset of the disease following the production of anti-Leptospira antibodies, initially mainly of the IgM class. The laboratory diagnosis of leptospirosis relies on the detection of leptospires by culture and PCR or by detection of anti-Leptospira antibodies in patients’ blood.

The microscopic agglutination test (MAT) is the cornerstone of the serodiagnosis of leptospirosis, because this assay has a high specificity and allows for the detection of presumptive group-specific antibodies.

The IgM-ELISA has the capacity to detect with a high sensitivity specific IgM antibodies as a sign of current or recent leptospirosis.
In the first few days of leptospirosis there is a diagnostic breach, as conventional serology and culture cannot provide early diagnosis. PCR is a successful method to detect Leptospira DNA in blood in the first week of infection. We apply a validated real-time PCR.