Fig. (1).Centrifugation-based enrichment method for spirochetes in blood. Venous blood is drawn into anticoagulant. Blood is thereafter centrifuged at 500 x g for 5 minutes, pelleting blood cells with most spirochetes remaining in the plasma. After transfer to a new test tube, the plasma is centrifuged at 5000 x g for 10 minutes to pellet bacteria. The supernatant is decanted, leaving spirochetes in the pellet. The suspended pellet is smeared onto a glass slide and stained with Giemsa for microscopic examination at 1000X magnification.