Patients admitted to an Intensive Care Unit (ICU) frequently have underlying cardiac dysfunction. Early interventions are sometimes difficult to initiate because of diagnostic uncertainty as to whether cardiac failure is present As B-type natriuretic peptide (BNP) has been shown to be increased in cardiac dysfunction, we sought to demonstrate whether BNP can be used as a screening tool for cardiac dysfunction in patients admitted to ICU. All patients admitted to a combined medical and surgical ICU over a four-week period were included in the study. BNP was measured on the point of admission using a hand-held meter. Clinicians were blinded from the measurement when diagnoses were made as to whether or not the patients had clinically significant cardiac dysfunction. Patients with cardiac dysfunction had a significantly higher level of BNP when compared to the non-cardiac dysfunction group: 516 +/- 385 pg/ml (n = 26) v 67 +/- 89 pg/ml (n = 58) (P < 0.0001) A BNP cut-off value at 144 pg/ml exhibited a 92% sensitivity, 86% specificity and 96% negative predictive value. The sensitivity improved to 96% when the analysis was confined to patients > or = 55 years. At this cut-off value, BNP is a strong predictor of cardiac dysfunction. BNP measurement offers a rapid and affordable way to screen for cardiac dysfunction in patients admitted to ICU. An increased BNP level warrants further cardiac investigations so as to implement early interventions for cardiac decompensation in ICU patients.