Systems, devices and methods for sequential analysis of complex matrix samples for high confidence bacterial detection and drug susceptibility prediction using a flow cytometer

Method for testing a sample of body fluid for the presence of bacteria and comprising the steps of adjusting the dilution of the sample to a predetermined concentration, of dividing the diluted sample into two batches defining a baseline-batch and a control-batch, of testing the baseline-batch at a time T0 with the flow cytometer to obtain enumerative baseline bacterial values, of culturing the control-batch in growth media between times T0 and T1, of testing the control-batch at time T1 with the flow cytometer to obtain enumerative control bacterial values, and of comparing the control values to the baseline values to determine a bacteria growth-ratio.