2042. Clinical Application of AspID PCR Alone and in Combination with Aspergillus Lateral Flow Device (AspLFD) in Bronchoalveolar Lavage (BAL) Fluid of Patients with Classic Risk Factors for Invasive Pulmonary Aspergillosis (IPA)

Abstract

BackgroundEarly diagnosis of IPA is challenging and has a direct impact on mortality. Several diagnostic modalities have been developed with variable performance. AspID is a new multiplex Aspergillus qRT-PCR assay and AspLFD is a rapid test that targets the Aspergillus specific antigen JF5; both tests were developed by OLM Diagnostics. We evaluated the performance characteristics of AspID used alone and in combination with AspLFD on BAL fluid of patients at high risk for IPA.MethodsSamples had been prospectively banked in our BAL repository. Forty-two samples, 14 from patients with proven/probable IPA by EORTC/MSG criteria and 28 from control patients without IPA, were tested with AspID and AspLFD. For AspID, DNA extraction and qRT-PCR were performed per manufacturer instructions. For AspLFD, 100 μL of sample was applied to the device. AspID and AspLFD results were each read by three different blinded observers. Only patient with a valid result for both tests were included in the analysis. Sensitivity, specificity, and accuracy of AspID alone and in combination with AspLFD were calculated.ResultsOf the 42 samples, 22 were excluded because the AspID internal extraction control showed the assay to be invalid and one sample was excluded because the AspLFD internal control line was not visible. Thus, 19 patients were analyzed, eight with IPA and 11 without IPA. Among eight IPA cases, seven were positive by AspID and one was negative; two tested positive by AspLFD and six were negative. Of the 11 control patients without IPA, four were positive by AspID and seven were negative; all 11 were negative by AspLFD. AspID sensitivity was significantly higher than that of AspLFD (87.5% vs. 25%, P = .0001), but specificity of AspLFD was superior to that of AspID (100% vs. 64%, P = 0.049). Accuracy was 74% for AspID and 68% for AspLFD. When deciding whether doing both tests was beneficial for diagnosis, union analysis showed the sensitivity to be 87.5% and the specificity to be 64%. Accuracy was not improved and remained at 74%.Conclusion AspID had higher sensitivity than AspLFD and AspLFD had higher specificity than AspID. Using both tests in combination did not improve the ability to diagnose IPA in patients with classic risk factors.Disclosures All authors: No reported disclosures.