Microfluidic flow filtration system for increasing the concentration of components contained in a fluid sample having a recirculation loop fluid circuitry, the fluid circuitry comprising the following elements: - a tangential flow filtration element having a feed inlet, a retentate outlet, a permeate outlet and a membrane capable for separating the fluid sample into a retentate stream and a permeate stream upon passage of the fluid sample into the tangential flow filtration element through the feed inlet, - an element for pumping for creating and driving a fluid flow of the fluid sample through the fluid circuitry and the tangential flow filtration element, - at least two elements for obtaining information about the properties of the fluid sample within the fluid circuitry; and - a plurality of conduits connecting the elements to the fluid circuitry through which a fluid stream of the fluid sample is conducted; wherein the minimal working volume of the fluid circuitry being defined by the minimal fluid volume retained in the elements and the conduits, such that the fluid can be recirculated in the fluid circuitry without pumping air through the fluid circuitry, is at most 5 ml, - the functionality of at least two elements of the group of elements of the circuitry is integrated in one integrated microfluidic element, - the one integrated microfluidic element defines a volume element having a volume which is at most one fourth of the minimal working volume of the fluid circuitry, - the integrated microfluidic element integrates the functionality of at least two elements for obtaining information about the properties of the fluid sample, and - one element for obtaining information about the properties is an optical measuring element for determining the concentration of the components contained in the fluid sample and - one element for obtaining information about the properties is a measuring element for determining the viscosity of the fluid sample. - a tangential flow filtration element having a feed inlet, a retentate outlet, a permeate outlet and a membrane capable for separating the fluid sample into a retentate stream and a permeate stream upon passage of the fluid sample into the tangential flow filtration element through the feed inlet, - an element for pumping for creating and driving a fluid flow of the fluid sample through the fluid circuitry and the tangential flow filtration element, - at least two elements for obtaining information about the properties of the fluid sample within the fluid circuitry; and - a plurality of conduits connecting the elements to the fluid circuitry through which a fluid stream of the fluid sample is conducted; - the functionality of at least two elements of the group of elements of the circuitry is integrated in one integrated microfluidic element, - the one integrated microfluidic element defines a volume element having a volume which is at most one fourth of the minimal working volume of the fluid circuitry, - the integrated microfluidic element integrates the functionality of at least two elements for obtaining information about the properties of the fluid sample, - one element for obtaining information about the properties is an optical measuring element for determining the concentration of the components contained in the fluid sample and - one element for obtaining information about the properties is a measuring element for determining the viscosity of the fluid sample.