Dynamic range and sensitivity of the Campylobacter coli and Campylobacter jejuni real-time PCR assays with samples containing roughly equal genome copies of both species. The linear range of each real-time PCR assay was determined using C. coli CIP 70.81 and C. jejuni NCTC 11168 standard DNA together. Standard curves of 10-fold serial dilution of both C. coli and C. jejuni standard DNA (roughly from 101 to 108 genome copies of each species per PCR reaction) by (a) C. coli real-time PCR assay and by (b) C. jejuni real-time PCR assay are reported, each dot representing the result of duplicate amplification of each dilution. The coefficients of determination and the slopes of each regression curve are indicated. The standard curves are obtained by correlation of the threshold cycle values (Ct) and log10 input genome copy number (Log CO) from the amplification plot.