In this VetGirl podcast, we review the clinicopathologic testing for leptospirosis. The diagnosis of canine leptospirosis is based on clinical suspicion, clinical signs, and clinicopathologic results consistent with leptospirosis. Clinicopathologic findings consistent with leptospirosis include the presence of: neutrophilia, a left shift, lymphopenia, a mild to moderate non-regenerative anemia, hemoconcentration (seen with dehydration), hemolysis (seen with cattle), thrombocytopenia (seen in up to 58% of dogs), azotemia (seen in > 80-90% of dogs), increased liver enzymes (including increases in ALT, AST, ALP, and total bilirubin; these changes are almost always seen with concurrent azotemia with leptospirosis), electrolyte abnormalities (e.g., hypokalemia, hyponatremia, hypochloridemia, hyperphosphatemia), and increased creatinine kinase. Additional findings consistent with leptospirosis include isosthenuria, bilirubinuria, hematuria, glucosuria, proteinuria, and evidence of coagulopathy (e.g., increased fibrinogen, FDP, FSPs). Prolonged PT or PTT may be seen in 6-50% of dogs with leptospirosis.