iga od 0 42 was also detectable while nearly no anti hcv igm was present od 0 02 fig1 b statistically the mean od of anti hcv of the igg and igm class is significantly reduced in oral fluid compared to serum p lt 0 01 while the od of iga class anti hcv is not significantly different p gt 0 01 unexpectedly in a number of oral fluid samples possessing low anti hcv igg levels a significant amount of anti hcv iga was detectable fig1 b which might contribute to a higher overall od and thus render a positive result indeed the ability to detect anti hcv of the iga class may also increase the likelihood of detection early on during the course of infection as iga is known to be present during the earliest stages of the immune responses to infections freihorst and ogra 2001 an investigation was then conducted to determine whether the detection of multiple classes of anti hcv antibodies instead of igg alone could increase the sensitivity of the ortho hcv 3 0 elisa in a modified oral fluid based format paired oral fluid serum samples from 127 known hcv seropositive and 31 seronegative donors were screened using the hcv 3 0 assay according to the manufacturer 39 s instructions using the monoclonal anti human igg peroxidase detection antibody using serum samples 100 sensitivity and specificity with the hcv 3 0 assay was achieved table i because there is no accepted cutoff value for oral fluid in the hcv 3 0 kit sensitivity and specificity were determined by roc analysis at.