Reevaluating Limits Of Detection Of 12 Lateral Flow Immunoassays For The Detection Ofyersinia Pestis,Francisella Tularensis, Andbacillus Anthracisspores Using Viable Risk Group-3 Strains

Aim Rapid detection of biological agents in biodefense is critical for operational, tactical and strategic levels as well as for medical countermeasures.Yersinia pestis,Francisella tularensis,andBacillus anthracisare high priority agents of biological warfare or bioterrorism and many response forces use lateral flow assays (LFAs) for their detection. Several companies produce these assays, which offer results in short time and are easy to use. Despite their importance, only few publications on the limits of detection (LOD) for LFAs are available. Most of these studies used inactivated bacteria or risk group-2 strains. As the inactivation process in previous studies might have affected the tests' performances, it was our aim in this study to determine and compare the LOD of several commercially available LFAs using viable risk group-3 strains. Methods and Results Lateral flow assays from four different companies for the detection of following bacteria were evaluated:Y. pestis, F. tularensisandB. anthracisspores. Two independent quantification methods for each target organism were applied, in order to ensure high quantification accuracy. LODs varied greatly between tests and organisms and ranged between 10(4)forY. pestis-tests and as high as >10(9)for oneB. anthracis-test. Conclusion This work precisely determined the LODs of LFAs from four commercial suppliers. The herein determined LODs differed from results of previous studies. This illustrates the need for using accurately quantified viable risk group 3-strains for determining such LODs. Significance and Impact of the Study Our work bridges an important knowledge gap with regard to LFA LOD. The LODs determined in this study will facilitate better assessment of LFA-results. They illustrate that a negative LFA result is not suited to exclude the presence of the respective agent in the analyzed sample.