Table 1.
Performances of dPCR systems used in the study for detection and quantification of M. avium subsp. paratuberculosis, L. monocytogenes, and F. tularensis.
| M. avium subsp. paratuberculosis | L. monocytogenes | F. tularensis | |
|---|---|---|---|
| Key Characteristics of dPCR Assay (QX200) | |||
| Dynamic Range (fg per μL)* | 102–105 | 101–104 | 100–103 |
| Dynamic Range (Log10 copies/μL)◦ | 1–4 | 1–4 | 0–3 |
| LOD—n◦ of target copies/μL | 18.120 ± 2.946# | 10.040 ± 1.391# | 2.204 ± 0.847 |
| LOQ—n◦ of target copies/μL | 18.120 ± 2.946# | 10.040 ± 1.391# | 27.240 ± 3.295 |
| Intra-run Variation: Range of Coefficients of variation (five dilutions tested in five replicates) | ±0.9 to ±15.7% | ±3.3 to ±14.1% | ±4.4 to ±34.0% |
| Inter-run Variation: Range of coefficient of variation (five dilutions tested five times in two independent replicate runs) | ±6.8 to ±11.9% | ±2.0 to ±5.6% | ±1.0 to ±25.4% |
| Key Characteristics of dPCR Assay (Quant Studio 3D) | |||
| Dynamic Range (fg per μL)* | 101–105 | 101–104 | 100–103 |
| Dynamic Range (Log10 copies/μL)◦ | 0–4 | 1–4 | 0–3 |
| LOD—n◦ of target copies/μL | 2.097 ± 1.345 | 13.813 ± 2.858# | 3.367 ± 1.547 |
| LOQ—n◦ of target copies/μL | 17.769 ± 3.364 | 13.813 ± 2.858# | 31.539 ± 4.758 |
| Intra-run Variation: Range of Coefficients of variation (from five dilutions tested in five replicates) | ±3.4 to ±64.3% | ±5.9 to ±34.6% | ±4.7 to ±39.1% |
| Inter-run Variation: Range of coefficient of variation (five dilutions tested five times in two independent replicate runs) | ±6.7 to ±22.6% | ±3.1 to ±8.82% | ±2.1 to ±8.4% |
*
These ranges were determined considering the positive signals at LOD level obtained with the same genomic DNA standards used for evaluate the performances of qPCRs.
◦
These ranges were determined considering the LOD.
#
The value is identical for LOD and LOQ because all replicates were positive and the coefficient of variation is lower than 25%; further details in the material and method section.