title: Importance and interpretation of intermediate (gray zone) amino-terminal pro-B-type natriuretic peptide concentrations.
abstract: Amino-terminal pro-B-type natriuretic peptide (NT-proBNP) values between the cut point of 300 ng/L for "ruling out" acute heart failure (HF) and the consensus-recommended age-adjusted cut points for "ruling in" acute HF are referred to as intermediate or gray zone values, which may be seen in approximately 20% of patients with dyspnea in the emergency department. Knowledge of the differential diagnosis of the causes of a gray zone NT-proBNP finding is useful to ascertain the correct diagnosis. Possible causes include cardiac ischemia, atrial fibrillation, and infectious/inflammatory pulmonary diseases. Importantly, a gray zone NT-proBNP result is not associated with a benign prognosis. Regardless of the cause, it should not be ignored because it is a "negative" result. Patients with a gray zone NT-proBNP value are at higher risk for hazard compared with those with a negative NT-proBNP result.
authors.affiliation: Department of Cardiology, Academic Hospital, Maastricht, The Netherlands.
authors.forename: Roland R J
authors.initials: RR
authors.lastname: van Kimmenade
authors.forename: Yigal M
authors.initials: YM
authors.lastname: Pinto
authors.forename: James L
authors.initials: JL
authors.lastname: Januzzi
mesh_terms: D015415:Biomarkers / Q000097:blood; D003937:Diagnosis, Differential; D006333:Heart Failure / Q000097:blood* / Q000175:diagnosis; D006801:Humans; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D011379:Prognosis; D011498:Protein Precursors; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D010446:Peptide Fragments; D011498:Protein Precursors; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain