Acute-phase serum specimens are tested and reported as received. The test results report will also indicate when the convalescent-phase serum should be collected. ViroMed holds all acute- phase sera at -20°C or less for 4 months. When the convalescent-phase serum is submitted, the acute- and convalescent-phase sera are tested in parallel to detect if IgG antibodies have appeared or increased in titer during the course of the illness. A four-fold or greater increase in IgG antibody titer between acute and convalescent specimens, along with clinical symptoms, can be indicative of acute infection.

An alternative approach to the diagnosis of an acute-phase illness is to demonstrate the presence of IgM specific antibody. The presence of IgM anti body in an acute-phase serum, together with clinical symptoms, can be indicative of acute infection.