Among the following, earliest test to be positive in leptospirosis is:: (A) Microagglutination test (MAT), (B) Leptospira culture of blood, (C) IgM ELISA of serum, (D) Macroagglutination test
Answer is C. Test for leptospirosis:Time to become positive:MAT(microscopic agglutination testing)Second week of illnessIgM ELISAWithin 3-5 daysBlood culture7-14 days after exposure(ref:Harrison's 17/e p1050)