To assess the association of diagnostic predictors available in the emergency department (ED) with the outcome diagnosis of severe acute respiratory syndrome (SARS).

This retrospective cohort study describes all patients from the Amoy Garden complex who presented to an ED SARS screening clinic during a 2-month outbreak. Clinical and diagnostic predictors were recorded, along with ED diagnoses. Final diagnoses were established independently based on diagnostic tests performed after the ED visit. Associations of key predictors with the final diagnosis of SARS were described.

Of 821 patients, 205 had confirmed SARS, 35 undetermined SARS and 581 non-SARS. Multivariable logistic regression showed that the strongest predictors of SARS were abnormal chest x-ray (odds ratio [OR] = 17.4), subjective fever (OR = 9.7), temperature >38°C (OR = 6.4), myalgias (OR = 5.5), chills and rigors (OR = 4.0) and contact exposure (OR = 2.6). In a subset of 176 patients who had a complete blood cell count performed, the strongest predictors were temperature ≥38ºC (OR = 15.5), lymphocyte count <1000 (OR = 9.3) and abnormal chest x-ray (OR = 5.7). Diarrhea was a powerful negative predictor (OR = 0.03) of SARS.

Two components of the World Health Organization case definition — fever and contact exposure — are helpful for ED decision-making, but respiratory symptoms do not discriminate well between SARS and non-SARS. Emergency physicians should consider the presence of diarrhea, chest x-ray findings, the absolute lymphocyte count and the platelet count as significant modifiers of disease likelihood. Prospective validation of these findings in other clinical settings is desirable.

To determine the ability of troponin I (TnI) measurement to predict the likelihood of a serious cardiac outcome over the subsequent 72 hours in patients presenting to the emergency department (ED) with symptoms suggestive of an acute coronary syndrome.

This prospective observational study enrolled consecutive patients presenting to 2 urban tertiary care hospital EDs over a 5-week period. Eligible patients included those for whom a TnI test was ordered within 24 hours of arrival and in whom no serious cardiac outcome occurred before the test result was available. Patients were followed for 72 hours and serious cardiac outcomes documented; these included cardiovascular death, myocardial infarction, congestive heart failure, serious arrhythmia and refractory pain. We calculated likelihood ratios (LRs) to describe the association of the TnI result with serious cardiac outcomes.

Of the 352 enrolled patients, 20 had a serious cardiac outcome within 72 hours of ED presentation. The derived LRs (and 95% confidence interval [CI]) were 0.5 (0.3–0.9) for TnI values <0.5 µg/L, 1.6 (0.4–6.5) for TnI values from 0.5 to 2.0 µg/L, 5.8 (1.7–19.5) for TnI values from >2.0 to 10.0 µg/L and 14.4 (4.8–42.9) for TnI values >10.0 µg/L.

TnI values >2.0 µg/L are associated with an increased probability of serious cardiac outcomes within 72 hours. TnI values between 0.5 and 2.0 µg/L are weakly positive predictors. TnI values <0.5 µg/L have LRs in the range of 0.5 and thus are weakly negative predictors, not substantially decreasing the likelihood of serious cardiac outcomes, particularly in patients with a moderate or high pretest probability.