Table 5.
Comparison of the detection limits of nested and real time PCR for P. falciparum, P. vivax P. malariae, P. ovale and P. knowlesi based on DNA extracted from 200 µl of whole blood.
| Parasitemia | (p/µl) | 100 | 20 | 10 | 1 | 0.5 | 0.25 | 0.12 | 0.06 | 0.03 |
|---|---|---|---|---|---|---|---|---|---|---|
| P. falciparum | Nested PCR | + | + | + | + | + | + | − | − | − |
| Real Time PCR | 28.6 ± 0.4 | 32.1 ± 0.3 | 32.3 ± 0.1 | 36.0 ± 0.2 | 37.3 ± 0.8 | 36.2 ± 0.7 | 38.0 ± NA | − | − | |
| Positive wells* | 3/3 | 3/3 | 3/3 | 3/3 | 3/3 | 2/3 | 1/3 | 0/3 | 0/3 | |
| P. vivax | Nested PCR | + | + | + | + | + | + | − | − | − |
| Real Time PCR | 28.8 ± 0.0 | 31.0 ± 0.1 | 31.6 ± 0.1 | 36.0 ± 0.9 | 36.6 ± 1.0 | 37.6 ± 1.3 | 38.0 ± NA | − | − | |
| Positive wells* | 3/3 | 3/3 | 3/3 | 3/3 | 3/3 | 3/3 | 1/3 | 0/3 | 0/3 | |
| P. malariae | Nested PCR | + | + | + | − | − | − | − | − | − |
| Real Time PCR | 35.4 ± 0.4 | 38.5 ± 1.0 | 38.1 ± 1.0 | 41.0 ± NA | − | − | − | − | − | |
| Positive wells* | 3/3 | 3/3 | 3/3 | 1/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | |
| P. ovale | Nested PCR | + | + | + | + | − | − | − | − | − |
| Real Time PCR | 31.0 ± 0.2 | 33.0 ± 0.2 | 35.1 ± 0.8 | 36.3 ± 1.2 | − | − | − | − | − | |
| Positive wells* | 3/3 | 3/3 | 3/3 | 3/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | |
| P. knowlesi | Nested PCR | + | + | + | − | − | − | − | − | − |
| Real Time PCR | 29.0 ± 0.2 | 31.4 ± 0.2 | 34.0 ± 0.2 | 37.6 ± 0.3 | 37.3 ± 0.5 | 38.0 ± 0.5 | 38.6 ± NA | 40.3 ± NA | − | |
| Positive wells* | 3/3 | 3/3 | 3/3 | 3/3 | 3/3 | 2/3 | 1/3 | 1/3 | 0/3 |
Results are presented in mean Ct (cycle threshold) ± standard deviation according to the level of parasitemia (p/µl, parasite/µl). In bold and italics, the LoD chosen. NA non-applicable. *Number of positive well in each real time triplicate.