FIG. 1.
Amplification plots showing the analytical sensitivity of the real-time multiplex PCR assay for B. burgdorferi (A) and A. phagocytophilum (B). The results from the amplification of 10-fold serial dilutions ranging from 5 × 106 to 50 B. burgdorferi spirochetes (Ct values 17.3, 21.0, 23.1, 28.5, 32.8, and 33.9) and from 125 to 0.125 A. phagocytophilum-infected HL-60 cells (Ct values 20.6, 24.4, 28.2, and 32.6) are shown. Ct values represent the cycle (indicated on the x axis) at which the fluorescence intensity (indicated by relative fluorescence units on the y axis) reached the threshold level.