Figure 6

Pooled and individual detection of SARS-CoV-2 in saliva collected during the Fall 2021 semester (August 23- December 17). Pools with more than one positive sample and samples with no negative droplets were removed before analysis. (a) Concordance between letter and number pools. Pearson’s correlation coefficient, r = 0.974 (p < 0.0001). (b) Box and whisker plots of copies per reaction for letter and number pools. Data are plotted on a log₁₀ scale. Boxes extend from the 25th to 75th percentiles with median indicated by a line. The letter versus number pools comparison had a median of differences of 4. Asterisks (****) denote a p-value < 0.0001 as determined using Wilcoxon matched-pairs signed rank test. (c) Plot of pooled versus individual copies per reaction for letter (red) and number (blue) pools. Pearson’s r = 0.907 (p < 0.0001) and 0.929 (p < 0.0001) for letter and number pools, respectively. Green circles indicate paired pool samples that deviate from the trendline. The dashed line indicates the line of identity (x = y).