The present invention provides a synthetic nucleic acid sequence comprising 10-30 nucleotides of the N gene region and/or the 3' non-coding region of the SARS-associated coronavirus genome, and a synthetic nucleic acid sequence comprising 10-30 nucleotides of a nucleic acid sequence that is complementary to at least one of those regions. Also provided are compositions comprising the sequences, and uses of the sequences in diagnostic kits. The present invention further provides a primer set for determining the presence or absence of SARS-associated coronavirus in a biological sample, wherein the primer set comprises at least one of the synthetic nucleic acid sequences. Also provided are a composition comprising the primer set, and use of the primer set in a diagnostic kit. Finally, the present invention provides kits and methods for determining the presence or absence of SARS-associated coronavirus in a biological sample.