PURPOSE: Blood culture contamination is still a frequently observed event and 
may lead to unnecessary antibiotic prescriptions and additional hazards and 
costs. However, in patients hospitalized in tertiary care, true bacteremias for 
pathogens that are classically considered as contaminants can be observed. We 
assessed the diagnostic accuracy of procalcitonin for differentiating blood 
culture contamination from bacteremia in patients with positive blood cultures 
for potential contaminants.
METHODS: We carried out a retrospective, cross-sectional, observational study on 
consecutive patients hospitalized between January 2016 and May 2019 at the 
University Hospital of Nancy and who had a positive peripheral blood culture for 
a pathogen classically considered as a potential contaminant.
RESULTS: During the study period, 156 patients were screened, and 154 were 
retained in the analysis. Among the variables that were significantly associated 
with a diagnosis of blood culture contamination in univariate analyses, four 
were maintained in multivariate logistic regression analysis: a number of 
positive blood culture bottles ≤ 2 (OR 23.76; 95% CI 1.94-291.12; P = 0.01), 
procalcitonin < 0.1 ng/mL (OR 14.88; 95% CI 1.62-136.47; P = 0.02), 
non-infection-related admission (OR 13.00; 95% CI 2.17-77.73; P = 0.005), and a 
percentage of positive blood culture bottles ≤ 25% (OR 12.15; 95% CI 2.02-73.15; 
P = 0.006).
CONCLUSIONS: These data provide new evidence on the usefulness of plasma 
procalcitonin as a reliable diagnostic biomarker in the diagnostic algorithm of 
peripheral blood culture contamination among patients hospitalized in tertiary 
care.
CLINICAL TRIAL: ClinicalTrials.gov #NCT04573894.