2044. Utility of Serum Β-D Glucan Assay for Diagnosis of Invasive Fungal Infections in Solid Organ Transplant Recipients

BACKGROUND: Β-D glucan (BDG) assay is a noninvasive test for presumptive diagnosis of invasive fungal infections (IFI). The utility of BDG assay and cut off values for positive, intermediate or negative test has been primarily studied in patients with hematological malignancies. However, the role of BDG in solid-organ transplant (SOT) recipients is not well described. The aim of this study was to evaluate the utility of serum BDG assay for IFI diagnosis in SOT recipients. METHODS: We retrospectively reviewed 200 patients who underwent SOT at Mayo Clinic and had BDG assay done for suspected IFI between January 1, 2013 and April 1, 2018. IFI cases were classified as proven, probable, and possible using EORTC/MSG criteria. Cases where BDG assay was used for treatment response follow-up or where results were inconclusive were excluded. BDG assay was performed at Viracor Eurofins Clinical Diagnostics lab. For the purpose of this study, a value of ≥80 pg/mL was considered positive and <80 pg/mL (intermediate or negative) was considered negative. RESULTS: A total of 117 tests from 104 patients met study inclusion criteria. The mean patient age was 56.2 years and 71 (60.7%) were male. Type of SOT included kidney (64), liver (30), heart (26), pancreas (6), and lung (6). BDG assay was positive in seven out of 10 invasive aspergillosis, two out of 3 invasive candidiasis, three out of four pulmonary coccidioidomycosis, and one Pneumocystis jirovecii pneumonia (Table 1). Overall, BDG assay was positive in 72.7% of cases (16/22) where a BDG containing organism was the etiology of invasive infection (sensitivity). It was false-positive in seven cases where a BDG containing organism was not identified. Overall specificity of the assay was 92.6% (Table 2). CONCLUSION: BDG assay is a useful adjunctive diagnostic aid for distinguishing IFI cases from those without IFI in SOT recipients. DISCLOSURES: M. R. Sohail, TyRx Inc.: Investigator, Research support; Medtronic Inc.: Investigator, Research support; Medtronic Inc.: Consultant, Speaker honorarium; Spectranetics: Consultant, Speaker honorarium; Boston Scientific Corp: Consultant, Speaker honorarium.