OBJECTIVE:To investigate plasma brain natriuretic peptide (p-BNP) in consecutive primary care patients for heart failure screening. DESIGN: Open, descriptive. SETTING: Three primary care clinics, university hospital. SUBJECTS: 291 consecutive patients, > or =40 years. MAIN OUTCOME MEASURES: p-BNP and general practitioners estimated probability of CHF. RESULTS: Median p-BNP was 29 ng/L. In 42% p-BNP was >40 ng/L in the first sample. In 41 patients further investigated, median p-BNP was 98 ng/L, with a correlation between p-BNP and physicians' estimation of probability of heart failure (r=0.469, p