A comparative study of immunocapture ELISA and RT-PCR for screening clinical samples from Southern Greece for human influenza virus types A and B.

An immunocapture (IC) ELISA and reverse transcriptase (RT)-PCR assays were evaluated as screening methods for the detection of influenza virus types A and B in clinical samples collected from individuals presenting with influenza-like symptoms in Southern Greece. Standard virus isolation in embryonated hens' eggs was taken as the reference method. According to the reference method, 25 (16.7%) of the 150 clinical samples examined were infected by influenza viruses - 19 type A (H3N2) and 6 type B. The sensitivity of immunocapture ELISA was 64% and that for RT-PCR was 100%. The specificity of IC ELISA was 98% and by RT-PCR 97%. The positive diagnostic value of IC ELISA was 94% and of RT-PCR 86%, whereas the negative diagnostic values for IC ELISA and PCR were 93% and 100%, respectively. These findings confirm that RT-PCR provides significantly increased sensitivity over IC ELISA and can be of value in the management of regional influenza screening surveys conducted by the national public health services.