The invention features methods for rapidly and sensitively identifying molecular targets in medical, industrial, and environmental samples. The invention labels target molecules and then images them using large area imaging. Diagnostic tests based on the invention can be rapid, ultrasensitive, quantitative, multiplexed, and automated. A broad range of infectious agents (e.g., bacteria, viruses, fungi, and parasites) and molecules (e.g., proteins, DNA, RNA, hormones, and drugs) can be detected by the methods. The invention enables rapid, ultra-sensitive, cost-effective, and portable assays. The ability of the invention to detect low levels of target molecules rapidly and cost-effectively results from the combination of high intensity labeling, formats that facilitate rapid reaction kinetics, and large area imaging based using either instrumentation made from off-the-shelf commercial components or no instrumentation at all.
