An example of such a discrepancy was seen in Alkhumra hemorrhagic fever studies treated with IFN-α2a, as the concentrations required to reduced infection by 50% differed from 684 (+/- 499) U/mL for CPE (metabolic-cell viability assay) and 12 (+/- 6) U/mL for virus titres (qRT-PCR) [63]. This evidence concerns the gene IFNA2 and infection.