25 Ago Combined use of serum (1,3)-β-D-glucan and procalcitonin for the early differential diagnosis between candidaemia and bacteraemia in intensive care units

Background: This study was aimed to assess the combined performance of serum (1,3)-β-D-glucan (BDG) and procalcitonin (PCT) for the differential diagnosis between candidaemia and bacteraemia in intensive care units (ICU) in two teaching hospitals in Italy.
Methods: From June 2014 to December 2015, all adult patients with proven candidaemia or bacteraemia plus BDG and PCT measured closely to the index culture, were included. The diagnostic performance of BDG and PCT, either separately or in combination, was assessed by calculating their sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratio (LR+ and LR-). Changes from pre-test to post-test probabilities of the two diseases were inferred from Fagan’s nomograms.
Results: 166 patients were included, 73 with candidaemia (44%) and 93 with bacteraemia (56%). When both markers indicated candidaemia (BDG ≥80 pg/ml and PCT <2 ng/ml) they showed higher PPV (96%) compared to 79% and 66% of BDG or PCT alone, respectively. When both markers indicated bacteraemia (BDG <80 pg/ml and PCT ≥2 ng/ml), their NPV for candidaemia was similar to that of BDG alone (95% vs. 93%). Discordant results (i.e., one marker indicating candidaemia and the other bacteraemia) only slightly altered the pre-test probabilities of the two diseases.
Conclusions: The combined use of PCT and BDG could be helpful in the diagnostic workflow for critically-ill patients with suspected candidaemia.