ABSTRACT
<p><b>INTRODUCTION</b>Singapore was one of 29 countries worldwide affected by severe acute respiratory syndrome (SARS) in 2003.</p><p><b>MATERIALS AND METHODS</b>There were 238 cases identified during the outbreak. We performed a retrospective analysis of the clinical and laboratory data of 234 patients admitted to Tan Tock Seng Hospital and Singapore General Hospital.</p><p><b>RESULTS</b>The mean age of patients was 21 years, 31.6% of patients were males and 41.8% were healthcare workers. At presentation, the common symptoms were fever, myalgia, cough and headache; rhinorrhoea was uncommon. On admission, 21% had leukopenia, 18% had thrombocytopaenia, 29% had hyponatraemia, 31% had hypokalaemia, 21% had transaminitis. Polymerase chain reaction (PCR) testing of respiratory and stool samples provided the best yield at the end of the first week of illness. Thirty-two patients were initially not recognised as probable SARS and were reclassified when the serology test results were available. The chief reasons for not identifying these patients early were persistently normal chest X-rays (68.8%), very mild presentation (43.8%) and the presence of a concomitant illness (12.5%). Overall, 12% of the patients were probable SARS with atypical presentations. Overall mortality was 11.8%.</p><p><b>CONCLUSION</b>Patients infected with the SARS coronavirus had a wide clinical presentation with non-specific symptoms.</p>