This is a prospective, non-interventional, multi-center study assessing the clinical specificity of the Anthrax LF Dx System using venous blood samples collected from presumptive anthrax negative adult male and female healthy and symptomatic subjects (non- B. anthracis infected).~Up to 500 subjects may be enrolled to meet the goal of 440 evaluable subjects (220 healthy and 220 symptomatic). Subjects will have one venous blood sample collected from a single time-point tested with the Anthrax LF Dx System. At each clinical site, specimens will be randomly selected such that 10% (40 of 400) of all subjects' venous blood samples (total of 40 [20 healthy and 20 symptomatic]) will be spiked with recombinant B. anthracis LF to prepare a contrived positive sample. An unblinded operator will prepare the spiked samples and provide both the spiked and neat samples to a blinded operator for testing on the Anthrax LF Dx System. Thus, the blinded operator will receive samples that could either be spiked (positive) or neat (presumed negative) to preserve the blind.
This study is intended to estimate the Anthrax LF Dx System specificity. Sensitivity will be estimated with 10% of the samples spiked with recombinant Bacillus anthracis lethal factor (LF) used to prepare contrived positive samples.