Table 1 VirScan’s sensitivity and specificity on samples with known viral infections.

Sensitivity is the percentage of samples positive for the virus as determined by VirScan out of all n known positives. Specificity is the percentage of samples negative for the virus by VirScan out of all n known negatives.

VirusSensitivity (n)Specificity (n)
HCV92% (26)*97%** (34)
HIV195% (61)*100% (33)
HSV197% (38)100% (6)
HSV290% (20)100% (24)

*We found that, although the false negative samples did not meet our stringent cutoff for enriching multiple unique peptides, they had detectable antibodies to a recurrent epitope. By modifying the criterion to allow for samples that enrich multiple homologous peptides that share a recurrent epitope as described in the text, the sensitivity of detecting HCV increases to 100%, and the sensitivity for detecting HIV increases to 97%. This modified criterion does not significantly affect specificity (fig. S13). **The one false positive was from an individual whose HCV-negative status was self-reported, but who had antibodies to as many HCV peptides as 23% of the true HCV-positive individuals and is likely to be HCV-positive now or in the past. It is possible that this individual was exposed to HCV but cleared the infection. If true, the observed specificity for HCV is 100%.