Immunofluorescence Direct (DFA) or indirect (IFA) immunofluorescence antibody staining techniques are capable of detecting influenza A and B viruses, and distinguish the viruses from each other as well as from other respiratory viruses [1••, 2••]. They have levels of sensitivity and specificity that come close to those of RT-PCR [28, 33] , and results are often available in a few hours [1••, 2••]. Although these tests have improved sensitivity over RIDT, they are more technically complex and require expertise in obtaining quality respiratory samples ( Table 2) .