Viral cultures were previously considered the "gold standard" for detecting viruses in specimens. Evaluating viral cultures takes a high level of expertise and can be rather time-consuming, with some cultures being held for up to 14 days. Another method, direct fluorescent antibody (DFA), has a quicker turnaround time of about 3 hours, but this also takes a high level of expertise as well as expensive equipment.
There are also several serological methods for the detection of viral infections these include: hemagglutinin inhibition, complement fixation, and enzyme-linked immunoassay (EIA).
Many facilities began utilizing rapid antigen direct tests due to a quick turnaround time, but it has since been discovered that these have a low level of sensitivity, and many infections can be missed when using only these antigen tests.
Additional, more sensitive tests have since been developed. These include nucleic acid amplification tests (NAAT), polymerase chain reaction (PCR), nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP), and most recently, multiplex PCR. For this course, only PCR and multiplex PCR will be described.
