Urine and plasma levels of fibrinopeptide B in patients with deep vein thrombosis and pulmonary embolism

Abstract

Background: Many patients with pulmonary thromboembolism remain undiagnosed, possibly because of the difficulty clinicians have in determining which patients merit work-up with accurate (but expensive) imaging techniques. Objectives: We present the first prospective clinical study of pulmonary embolism (PE) and deep venous thrombosis (DVT) detection using the FPB tot assay, which measures fibrinopeptide B and its first derivative, des-arginine fibrinopeptide B. Methods: Twenty three patients with signs or symptoms of PE or DVT were enrolled in the study prior to the performance of definitive testing. Using a novel immunoassay, FPB tot levels were measured in urine and plasma samples from patients as well as from healthy controls. Urine and plasma FPB tot levels were compared to the diagnostic results, as blindly adjudicated by one of the investigators. Patients were excluded if they withdrew ( n=1), had inconclusive diagnostic testing ( n=7), or did not give samples ( n=2 for urine, n=3 for plasma). Results: The mean FPB tot concentration in the urine of the ‘DVT/PE positive’ group was 78.4±35.2 ng/ml and 2.7±1.9 ng/ml in the ‘DVT/PE negative’ group ( p=0.03). The urine FPB tot concentrations in the ‘DVT/PE negative’ group were not significantly different from those in the healthy control group (2.2±0.4 ng/ml, p=0.40). The area under the ROC curve for urine FPB tot concentrations was 97.3±3.8%, suggesting a high degree of diagnostic accuracy. Plasma FPB tot concentrations were not significantly different between groups. Conclusions: Urine FPB tot levels may help detect patients with PE and DVT.