Effect of NT-proBNP testing on diagnostic certainty in patients admitted to the emergency department with possible heart failure.

Background: Difficulty in distinguishing congestive heart failure (HF) from other causes of dyspnoea in the emergency department (ED) may result in delay in appropriate treatment and referral. Although the diagnostic value of serum amino-terminal pro-B-type natriuretic peptide (NT-proBNP) is well documented, the impact on diagnostic certainty of providing these results to ED physicians is not well studied. We sought to determine the effect of providing NT-proBNP results on diagnostic certainty of physicians managing patients presenting to the ED with suspected HF.

Methods: A randomized controlled study was conducted in 68 patients presenting to the ED with dyspnoea. ED clinicians initially rated the probability of HF as the cause of dyspnoea without the knowledge of the result. A scale of 1-7 was used, with 1 representing a high degree of certainty of a diagnosis other than HF and 7 representing a high degree of certainty of HF being the cause of dyspnoea. In 38 patients, the ED physician then reassessed the probability of HF as the cause of dyspnoea after receiving the NT-proBNP result. A cardiologist blinded to the NT-proBNP result determined the final diagnosis after review of medical records and investigations.

Results: Providing the NT-proBNP result reduced diagnostic uncertainty, defined as a test score of 3-5, from 66% of cases to 18% of cases (P < 0.0001) and improved diagnostic accuracy from 53% to 71% (P = 0.016).

Conclusion: Measurement of NT-proBNP concentrations reduces diagnostic uncertainty and improves diagnostic accuracy in patients presenting to the ED with dyspnoea and possible HF.