A device for measuring target particles in a sample, comprising: a cartridge device, wherein the cartridge device comprises: an inlet configured for receiving the sample into the cartridge device; a fluidic structure fluidly connected to the inlet and configured for mixing at least a portion of the sample with at least a portion of a reagent to form one or more sample mixtures; a flow cell fluidly connected to the fluidic structure and configured for forming one or more sample streams from the one or more sample mixtures, wherein the flow cell has a fluidic channel having a core diameter chosen according to the sample stream diameter and the flow cell contains only the sample stream for analysis without a sheath flow, and wherein the flow cell comprises an optically transparent area configured for measuring an optical signal ( A, T ) from the sample streams to detect the target particles in the sample; and a flow sensor fluidly connected to the flow cell and configured for measuring a sensing signal ( T 1 , T 2 ) from the sample streams that enter the flow sensor ; wherein the fluidic structure comprises at least one basic fluidic unit that comprises: a chamber configured to accommodate a fluid; a venting port connected to the chamber , wherein the venting port is connected to a pneumatic pressure source pumping the sample from the chamber into the flow cell and into the flow sensor ; a microfluidic channel connected to the chamber ; and a valve on the microfluidic channel . an inlet configured for receiving the sample into the cartridge device; a fluidic structure fluidly connected to the inlet and configured for mixing at least a portion of the sample with at least a portion of a reagent to form one or more sample mixtures; a flow cell fluidly connected to the fluidic structure and configured for forming one or more sample streams from the one or more sample mixtures, wherein the flow cell has a fluidic channel having a core diameter chosen according to the sample stream diameter and the flow cell contains only the sample stream for analysis without a sheath flow, and wherein the flow cell comprises an optically transparent area configured for measuring an optical signal ( A, T ) from the sample streams to detect the target particles in the sample; and a flow sensor fluidly connected to the flow cell and configured for measuring a sensing signal ( T 1 , T 2 ) from the sample streams that enter the flow sensor ; wherein the fluidic structure comprises at least one basic fluidic unit that comprises: a chamber configured to accommodate a fluid; a venting port connected to the chamber , wherein the venting port is connected to a pneumatic pressure source pumping the sample from the chamber into the flow cell and into the flow sensor ; a microfluidic channel connected to the chamber ; and a valve on the microfluidic channel . a chamber configured to accommodate a fluid; a venting port connected to the chamber , wherein the venting port is connected to a pneumatic pressure source pumping the sample from the chamber into the flow cell and into the flow sensor ; a microfluidic channel connected to the chamber ; and a valve on the microfluidic channel . <EOS>