Figure 3. Analysis of parasite densities in clinical samples using absolute qPCR and microscopy.

Absolute quantitative qPCR was performed using plasmid DNA as the standard to analyze clinical samples. The log₁₀ parasite densities in terms of parasite/µl was determined from qPCR assays and compared to the log₁₀ parasite densities as determined by expert microscopist. The correlation coefficient of parasite densities measured using the two methods was calculated using the nonparametric Spearman correlation coefficient. There was a statistically significant correlation between parasite density measured by microscopy and absolute quantitative qPCR.