Evaluation of the LDBio ICT IgG/IgM lateral flow assay versus the Bordier Elisa assay for the diagnosis of chronic pulmonary aspergillosis in Nigeria.

Abstract

The detection of anti-Aspergillus antibodies is key for diagnosing chronic pulmonary aspergillosis (CPA). Available techniques are limited and pose a considerable challenge in resource-limited settings. The objective of this study was to evaluate the performance of the point-of-care test LDBio ICT IgG/IgM lateral flow assay (LDBio) versus that of the Bordier Elisa assay in a field study in Nigeria. Of the 97 serum samples tested in the CPA patient group, 71 tested positive by the LDBio assay with 69.4% sensitivity. In the non-CPA group, 286 of the 289 sera tested negative by the LDBio assay with 98.7% specificity. The Bordier test was positive for 97 of the 97 CPA serum samples tested, showing 100% sensitivity, significantly different from the LDBio test in detecting Aspergillus antibodies (P < 0.0001). However, there was no significant difference in the specificity between the two tests (P = 0.617). The results were in agreement for 353 of the 386 samples tested (91.5%), with a Cohen's kappa coefficient of 0.75, indicating substantial agreement between the LDBio and Bordier test results. The LDBio lateral flow assay (LFA) test is a simple and rapid point-of-care test that can be used in field studies in which the Elisa test is not available. The lower sensitivity of the LDBio LFA in our field study could have been due to A. fumigatus being the species involved in only 50%-60% of cases in Nigeria, with A. flavus being more frequent than in Northern countries.IMPORTANCEAvailable techniques for the detection of Aspergillus IgG are limited and pose a considerable challenge in resource-limited settings in terms of affordability, skilled personnel, equipment, and a regular power supply. A point-of-care test would address most of these challenges. The LDBio lateral flow assay (LFA) test is a simple and rapid point-of-care test that can be used in field studies in which the Elisa test is not available. When combined with clinical features, the LFA can be used as a screening tool for chronic pulmonary aspergillosis in settings such as ours; however, a lower sensitivity was observed compared to the Elisa.