Figure 1
From: Diagnosing norovirus-associated infectious intestinal disease using viral load
Percentage distribution of real time RT-PCR Ct values in IID cases and controls. Low Ct values correspond to high viral loads; the viral load decreases with increasing Ct value. 'EM cases' are IID cases positive by electron microscopy, 'RT-PCR cases' are IID cases negative by electron microscopy and subsequently positive by RT-PCR. Sample sizes: EM cases = 92, RT-PCR cases = 497, controls = 159.