TABLE 3.
Determination of the detection and quantification limits of R. equi choE, choE-IAC, and vapA Q-PCR assaysa
| Approx no. of genome eq/reaction | Confidence interval limitb
|
Signal ratio for assayc:
|
CT for assayd:
|
|||||
|---|---|---|---|---|---|---|---|---|
| Lower | Upper | choE | choE-IAC | vapA | choE | choE-IAC | vapA | |
| 1 × 106 | 997,600 | 1,003,300 | 9/9 | 9/9 | 9/9 | 19.83 ± 0.02 | 19.90 ± 0.04 | 18.80 ± 0.02 |
| 1 × 105 | 99,643 | 100,358 | 9/9 | 9/9 | 9/9 | 23.32 ± 0.05 | 23.40 ± 0.06 | 22.25 ± 0.06 |
| 1 × 104 | 9,887 | 10,113 | 9/9 | 9/9 | 9/9 | 26.05 ± 0.02 | 26.01 ± 0.03 | 25.60 ± 0.03 |
| 1 × 103 | 964 | 1,036 | 9/9 | 9/9 | 9/9 | 29.50 ± 0.02 | 29.60 ± 0.04 | 29.00 ± 0.03 |
| 1 × 102 | 89 | 111 | 9/9 | 9/9 | 9/9 | 32.88 ± 0.03 | 32.95 ± 0.05 | 32.20 ± 0.04 |
| 1 × 101 | 7 | 14 | 9/9 | 9/9 | 9/9 | 36.77 ± 0.15 | 36.80 ± 0.14 | 35.80 ± 0.12 |
| 1 | 0 | 2 | 6/9 | 6/9 | 7/9 | 38.38 ± 0.41 | 38.70 ± 0.34 | 38.20 ± 0.29 |
a
Nontemplate controls were negative in the three Q-PCR assays (CT values of >50 in all the replicates).
b
Calculated for the expected number of template molecules at each dilution at 95% confidence level.
c
Number of positive results out of nine reactions.
d
Cycle number at which fluorescence intensity equals a fixed threshold. Mean values ± standard errors of the means were calculated with a prefixed threshold of 200. Differences in CT values were statistically significant with P < 0.05.