Evaluation of WHO criteria for identifying patients with severe acute respiratory syndrome out of hospital: prospective observational study.

Objectives: To determine the clinical and radiological features of severe acute respiratory syndrome (SARS) and to evaluate the accuracy of the World Health Organization's guidelines on defining cases of SARS.

Design: Prospective observational study.

Setting: A newly set up SARS screening clinic in the emergency department of a university hospital in Hong Kong's New Territories.