Feasibility of serum galactomannan assay in hematologic malignancy patients with invasive fungal infections

Abstract

Objective To evaluate the feasibility of the serum galactomannan (GM) assay as a rapid detection method for the early diagnosis of invasive fungal infections (IFI) in haematological malignancy patients. Methods Thirty-nine patients with haematological malignancies at high risk of IFI were enrolled into this study. The criteria of high risk included fever (≥ 38℃) lasted for more than 96 hours, fever didn' t response to proper broad spectrum antibiotic or recurrenced after short period of response, and no antifungal drug was used in the last week. The GM assay in serum specimens were performed twice a week for 3 weeks. Thirty health donor were selected as control group to perform the serum GM assay. The sensitivity and specificity, the positive and negative predictive value (PV+, PV-) of GM assay in serum specimens were calculated and compared with traditional diagnosis methods. Results In the 39 patients, 31 patients were diagnosed as IFI by clinical evidence and the other 8 patients were diagnosed as bacteria infection. The cut-off of GM assay was 0.5. GM assay results showed that the positive rate, sensitivity, specificity, total consistent rate, PV+ and PV- were 80.6 %, 87.1%, 62.5%, 82.0%, 90.0 % and 55.6%, respectively. The Kappa rate was 0.474. In the 8 patients without IFI, 3 cases were GM positive and 2 BG positive. The time of the first positive GM assay was (2.8±4.8) d (ranged from 24 d before to 3 d after clinical diagnosis) before IFI was diagnosed. During antifungal treatment, the level of GM maintained highly in the patients with aggravation of IFI, and dropped with the IFI improving. Conclusion The results of GM assay were consistent with that of traditional IFI diagnosis. Compared with classical IFI diagnosis, the GM assay has the advantages of the early, rapid, and high sensitivity and specificity. Key words: Hematologic neoplasms; Invasive fungal infections; Hematologic malignancy; Galactomannan assay; Sensitivity and specificity