Abstract
The first cases of severe acute respiratory syndrome (SARS) were identified in November, 2002, in Guangdong Province, China. By July, 2003, the epidemic had spread worldwide, affecting 8, 088 individuals resulting in 774 deaths. Severe acute respiratory syndrome (SARS) is a new emerging disease that has affected many countries, with more than 8, 000 cases reported. A novel virus, the SARS associated coronavirus, has been identified as the causal agent. Researchers in several countries are working towards developing fast and accurate laboratory diagnostic tests for the SARS coronavirus (SARS-CoV). Polymerase chain reaction (PCR) can detect genetic material of the SARS-CoV in various specimens. However, existing PCR tests are very specific but lack sensitivity. This means that negative tests cannot rule out the presence of the SARS virus in patients. Current tests need to be further developed to improve sensitivity. Antibody tests detect antibodies produced in response to the SARS coronavirus infection. But they can be undetectable at the early stage of infection. ELISA (Enzyme Linked ImmunoSorbant Assay): a test detecting a mixture of IgM and IgG antibodies in the serum of SARS patients yields positive results reliably at around day 21 after the onset of illness. IFA (Immunof luorescence Assay): a test detecting IgM antibodies in serum of SARS patients yields positive results after about day 10 of illness.
