We compared the LOD of these multiplex NAT assays [40] with the results of our working PCR array in sensitivity of testing against these important viruses. The LOD for HBV are 38.1-195 geq/ml by ''Procleix Ultrio Tigris'' and 9.2-37. Other PCR-coupled techniques have been developed previously for highly-sensitive pathogens' detection that could reach the sensitivity of the assay up to 1 genome copy per PCR reaction. For example the bioactive amplification with probing (BAP), utilizing a nested PCR and magnetic bead-based hybridization with the specific probe, has been developed for the detection of bovine and avian viruses [41] [42] [43] . In spite of the exceeding sensitivity of such assays targeting a single virus, it may be difficult to adapt the approach or method to meet the main objective of simultaneous detection of multiple target viral pathogens by an array using universal PCR conditions.