[The effect of albumin on (1, 3)-β-D-glucan for diagnosis of invasive fungal infections].

Objective: To explore the diagnostic value of plasma ( 1, 3 )-β-D-glucan test ( G test ) in diagnosis of invasive fungal infections ( IFI ) and the influence of albumin on G test.

Methods: A prospective observational study was conducted. 267 patients admitted to medical intensive care unit ( MICU ) of Dalian Municipal Central Hospital from January 21st, 2012 to October 31st, 2014 were enrolled. According to IFI guideline, the patients were divided into without IFI group ( n = 35 ), possible IFI group ( n = 70 ), hypotheticle IFI group ( n = 145 ) and proven IFI group ( n = 17 ). G test was examined routinely using microbiology kinetic rapid reader MB-80.The different threshold values were calculated on G test. The difference among G tests, fungal culture and clinical diagnosis were compared. The results of G test ahead of and post albumin administration in each group were compared, and the value of G test for diagnosis of IFI during albumin infusion was evaluated.

Results: When the cut-off value was 20 ng/L for IFI diagnosis, higher sensitivity ( 79.8% ), specificity ( 87.9% ), and Youden index ( 67.7% ) were found. The positive rates of G test, fungal culture and clinical diagnosis of IFI were 57.7% ( 154/267 ), 60.7% ( 162/267 ) and 54.3% ( 145/267 ) respectively, without showing significant differences ( all P > 0.05 ). The result of G test ( ng/L ) was not obviously changed after albumin administration compared with that before in without IFI, possible IFI, hypotheticle IFI, and proven IFI groups ( without IFI group: 11.25±2.33 vs. 10.99±1.07, t = -1.723, P = 0.085; possible IFI group: 53.14±5.53 vs. 49.22±8.11, t = -0.395, P = 0.693; hypotheticle IFI group: 90.30±9.38 vs. 85.41±10.11, t = 710.500, P = 0.860; proven IFI group: 100.98±19.24 vs. 103.21±17.66, t = 653.000, P = 0.449 ). Prior to the administration of albumin, sensitivity, specificity, positive predictive value ( PPV ), negative predictive value ( NPV ) and Youden index were 79.8%, 87.9%, 45.6%, 96.7%, 67.7%, respectively. However, after the administration of albumin, they were 81.5%, 85.7%, 44.8%, 96.5%, and 67.2%, respectively, without significant difference.

Conclusions: G test is method for early diagnosis of IFI. The sensitivity and specificity are higher with 20 ng/L as the critical value. The result of G test is not interfered by albumin administration.