Abstract: Some aspects of the invention provide for a method for detecting metabolic activity in a sample by obtaining a sample, illuminating the sample at a plurality of time points, measuring transmitted light from a marker of metabolic activity in the sample at the plurality of time points, and detecting the presence or absence of metabolic activity from a change in the transmitted light at the plurality of time points. Other aspects of the invention provide for a method for detecting metabolic activity in a sample by providing a sample have a detectable marker therein that is reflective of metabolic activity in the sample, producing an amplified signal from the marker, measuring the amplified signal at a plurality of time points, and detecting metabolic activity from a change in the signal. Additional aspects provide for a system for detecting metabolic activity in a sample.