MycoLight? Fluorimetric CTC Live Bacteria Quantification Kit. The CTC Flow Cytometric Live Bacteria Assay Kit provides an easy and convenient method for evaluating bacterial health and vitality as a function of the respiratory activity. CTC itself is non-fluorescent, once reduced by the electron transfer system of viable bacterial cell surface, red and insoluble fluorescent CTC formazan is formed and can be detected with a flow cytometer. Dead bacteria that are not respiring or unhealthy bacteria that respire at a lower rate will produce none or less red fluorescent with CTC staining, thus providing a semi-quantitative measure of health status of bacteria population.