Emerging, rapid, multivalent, microbial diagnostic technologies can produce results in hours, as contrasted to the standard methods that require at least the better part of a week. Used in bioterrorism surveillance in medical settings, the new biodetectors could significantly reduce the time between a covert attack and its detection. By how much is determined by the intensity of sampling. If used to screen all patients reporting flu-like symptoms to their doctors, this basic level of “front-line” sampling would reduce life-threatening medical floundering and missteps and give responders 3–5 days of warning that they otherwise would not have had. Being miniaturized and amenable to mass production, these devices could reduce the cost of screening to a fraction of current costs and so it is tempting to imagine their use in more intensive bioterrorism screening programs aimed at the apparently healthy population, programs that could detect a covert attack even before the victims felt ill. This article examines the tradeoffs between surveillance effort and probability of detection for such programs. Dual-use deployment, where the biodetector provides some medically useful information in addition to bioterrorism surveillance, is discussed.