Abstract: An apparatus and system for integrating flow cytometry measurements into a medical procedure. An example integrated flow sampling apparatus may include a discharge tube, fluidly connecting a catheter within a patient to a drainage bag. In addition, the apparatus may include an integrated flow sampling cassette. The integrated flow sampling cassette may include a bypass tube having two ends, each fluidly connected to the discharge tube. The bypass tube may further include a flow detection region enabling detection of a flow of discharge fluid through the bypass tube; an imaging region enabling detection of cells within the flow of discharge fluid; and a flow control valve enabling impedance of the flow of discharge fluid through the bypass tube. The apparatus may additionally include protrusions extending into the discharge tube and facilitating the entry of the discharge fluid into the bypass tube and subsequently back into the discharge tube.