Testing the performance of the newly formatted lateral flow device for the diagnosis of invasive pulmonary aspergillosis

KA Linder1,2, CA Kauffman1,2, MH Miceli1,2

Author address: 

1Division of Infectious Diseases, University of Michigan, Ann Arbor, MI, USA 2Division of Infectious Diseases, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA

Abstract: 

Introduction: Diagnosis of invasive pulmonary aspergillosis (IPA) remains challenging. In recent years, a lateral flow device (LFD) that uses an Aspergillus-specific humanized monoclonal antibody JF5 has become available for rapid diagnosis of IPA. Most recently, the original prototype LFD has been reformatted for improved performance and mass manufacture. The new LFD formulation utilizes the same antibody and targets the same antigen as the original device. We evaluated the performance of the newly formatted LFD in bronchoalveolar lavage (BAL) specimens for the diagnosis of IPA in high-risk patients.

Methods: Of 1211 BAL specimens obtained from 9/2014-8/2015, 1146 were excluded because the patients (pt.) were at low risk for IPA, were <18 years old, or the sample was inadequate for testing. BAL samples from 65 high-risk pt. were included in the study. Pt. were classified as having proven, probable, possible, or no IPA based on EORTC/MSG criteria. Results were interpreted independently by 2 study team members and graded from 1+ to 3+. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.

Results: Four pt. had probable IPA; 10, possible IPA; and 51 no IPA. 52 pt. (80%) had at least one classic risk factor for IPA: solid organ transplantation (25%), autoimmune disease on chronic immunosuppression (27%), hematologic malignancy or hematopoietic cell transplantation (58%). Five samples were positive with the new LFD assay: 2 probable, 1 possible, & 2 with no IPA (both weakly +).

Evaluating cases of probable IPA versus cases of no IPA, sensitivity of the LFD was 50% (95%CI, 6.8-93.2%), specificity was 96% (95%CI, 86.5-99.5%), PPV was 50%, & NPV was 96%. Including both probable and possible IPA, sensitivity decreased to 21% (95%CI, 4.7-50.8%), specificity remained 96%, PPV was 60%, & NPV was 82%.

Conclusions: Using the new formulation of the Aspergillus LFD, antigen was detected in 2 of 4 cases of probable IPA and 1 case of possible IPA. The new LFD platform was user-friendly & test results were easy to interpret. Our results are limited by the small number of IPA cases included; future studies should include a larger sample size of pt. at high risk for IPA. 

2018

Full conference title: 

The 8th Advances Against Aspergillus, Lisbon Conference Center, Lisbon, Portugal
    • AAA 8th (2018)