A system comprising: (a) a network device comprising: a single network device inlet; a single network device outlet; and an aspiration pressure means for providing movement of liquid sample through said network device; and more than one network unit in fluid communication with said single network device inlet and said single network device outlet, wherein said more than one network unit are in parallel and each of said more than one network unit comprises a plurality of microchannels comprising: (i) a single network unit inlet in fluid communication with said single network device inlet and a single network unit outlet in fluid communication with said single network device outlet; (ii) at least one parent microchannel branching into two daughter microchannels of unequal diameter or width, at least one of said two daughter microchannels branching at an angle from 20° to 80°, measured relative to the axis of said at least one parent channel, and (iii) at least one converged microchannel converging from two microchannels at an angle from 20° to 80°, measured relative to the axis of said at least one converged microchannel; and (b) an analysis device comprising: (i) one or more sensors for capturing a measurement related to a sample of red blood cells, wherein said measurement being microchannel flow rate (Q i), wherein the rate of flow of blood is measured in every microchannel of the network device, and (ii) a processor comprising a memory device configured to compare said captured measurements to measurements stored in a database of healthy red blood cells to determine the microvascular fitness of said sample of red blood cells. (a) a network device comprising: a single network device inlet; a single network device outlet; and an aspiration pressure means for providing movement of liquid sample through said network device; and more than one network unit in fluid communication with said single network device inlet and said single network device outlet, wherein said more than one network unit are in parallel and each of said more than one network unit comprises a plurality of microchannels comprising: (i) a single network unit inlet in fluid communication with said single network device inlet and a single network unit outlet in fluid communication with said single network device outlet; (ii) at least one parent microchannel branching into two daughter microchannels of unequal diameter or width, at least one of said two daughter microchannels branching at an angle from 20° to 80°, measured relative to the axis of said at least one parent channel, and (iii) at least one converged microchannel converging from two microchannels at an angle from 20° to 80°, measured relative to the axis of said at least one converged microchannel; and a single network device inlet; a single network device outlet; and an aspiration pressure means for providing movement of liquid sample through said network device; and more than one network unit in fluid communication with said single network device inlet and said single network device outlet, wherein said more than one network unit are in parallel and each of said more than one network unit comprises a plurality of microchannels comprising: (i) a single network unit inlet in fluid communication with said single network device inlet and a single network unit outlet in fluid communication with said single network device outlet; (ii) at least one parent microchannel branching into two daughter microchannels of unequal diameter or width, at least one of said two daughter microchannels branching at an angle from 20° to 80°, measured relative to the axis of said at least one parent channel, and (iii) at least one converged microchannel converging from two microchannels at an angle from 20° to 80°, measured relative to the axis of said at least one converged microchannel; and (i) a single network unit inlet in fluid communication with said single network device inlet and a single network unit outlet in fluid communication with said single network device outlet; (ii) at least one parent microchannel branching into two daughter microchannels of unequal diameter or width, at least one of said two daughter microchannels branching at an angle from 20° to 80°, measured relative to the axis of said at least one parent channel, and (iii) at least one converged microchannel converging from two microchannels at an angle from 20° to 80°, measured relative to the axis of said at least one converged microchannel; and (b) an analysis device comprising: (i) one or more sensors for capturing a measurement related to a sample of red blood cells, wherein said measurement being microchannel flow rate (Q i), wherein the rate of flow of blood is measured in every microchannel of the network device, and (ii) a processor comprising a memory device configured to compare said captured measurements to measurements stored in a database of healthy red blood cells to determine the microvascular fitness of said sample of red blood cells. (i) one or more sensors for capturing a measurement related to a sample of red blood cells, wherein said measurement being microchannel flow rate (Q i), wherein the rate of flow of blood is measured in every microchannel of the network device, and (ii) a processor comprising a memory device configured to compare said captured measurements to measurements stored in a database of healthy red blood cells to determine the microvascular fitness of said sample of red blood cells.