Table 2.
Properties of tests that are used to measure the presence of virus or viral infection
| Principle of assay | Example | Infectivity test | Detection limit (particles per gram) |
|---|---|---|---|
| Visualisation of particles | EM | No | 105–6 |
| Detection of viral protein | ELISA, latex tests | No | 105 |
| Detection of genome | Probe hybridisation | No | 104 |
| Detection of genome | RT-PCR | No | 101–3 |
| Screen for effect on living cells | Cell culture isolation (where feasible) | Yes | 100–1 |
| Measurement of exposure | Antibody assays | Yes | Window of detection varies by type of antibody. IgM indicates recent infection |