Figure 1. Association between specimen age and PCR amplification success using primers ITS1F and ITS4.

Pearson Chi-square test of independence (N = 2763, d.f. = 2) significant at p<0.0001. Asterisks denote categories with standardized adjusted residuals significant at a Bonferroni-corrected α = 0.00833. See Table S2 for data and post hoc test results.