Detection of (1→3)‐β‐D‐glucan in same‐day urine and serum samples obtained from patients with haematological malignancies

Serum 1,3‐beta‐d ‐glucan (BDG) testing is an established diagnostic marker for invasive fungal infections (IFI) among patients with haematological malignancies. In contrast limited data exist regarding the application of urine BDG testing. Same‐day midstream urine and serum screening samples were collected in adult patients with underlying haematological malignancies. A total of 80 urine samples from 46 patients were investigated: Twenty‐six had positive corresponding serum BDG >120 pg ml^?1, 27 intermediate (60–80 pg ml^?1), and 27 negative serum BDG (<25 pg ml^?1). A significant positive correlation between BDG in serum and urine samples was observed (P = 0.025; r = 0.252). Sensitivity, specificity, positive predictive value and negative predictive value (compared with same‐day serum results) were: 42%, 76%, 46%, 73% when using an 80 pg ml^?1 urine cut‐off, and 35%, 96%, 82%, 75% for a 250 pg ml^?1 cut‐off. Urine BDG seemed to be higher in samples obtained from patients with probable IFI (n = 13, median 145, IQR 22–253) compared to those from patients without IFI (n = 56, median 24, IQR 15–88) but the difference was not significant (P = 0.069). Overall correlation of same‐day urine BDG and serum BDG was moderate. However, urine BDG testing may warrant further investigation in larger studies, as high‐positive urine results correlated with high‐positive corresponding serum levels and clinical performance was comparable to serum BDG.