A method for determining agglutination of a biological liquid by measuring a change in hydrodynamic resistance of the biological liquid flowing through a microfluidic channel of a microfluidic device, the method comprising the steps of: a) calibrating the microfluidic device by calculating a calibrated value of hydrodynamic resistance of a sequence of droplets of a known biological liquid in which agglutination occurred and a calibrated value of a sequence of droplets of a known biological liquid in which agglutination did not occur, according to steps (b)-(i) which are then performed for a tested biological liquid; b) filling the microfluidic reaction channel with a hydrophobic continuous liquid phase, the microfluidic reaction channel having detectors (6, 7) spaced at the distance defining measurement section of the microfluidic reaction channel, wherein the pressure inducing the flow in microfluidic reaction channel constitutes the difference in pressure over the reservoir with the continuous phase and the atmospheric pressure; c) introducing into the microfluidic reaction channel a first reference droplet being a droplet of the biological liquid merged with saline or PBS or water and immiscible with the continuous phase; d) causing the first reference droplet to flow through the microfluidic reaction channel having a measurement section; e) measuring the time of flow of the first reference droplet through the measurement section of the microfluidic reaction channel; f) introducing into the microfluidic reaction channel a second reference droplet being the same as the first reference droplet, followed by a sequence of 1 to 1000 test droplet(s), the test droplet(s) being droplet(s) of the biological liquid, the same as comprised in reference droplets, and the agglutination reagent and immiscible with continuous phase; g) causing the second reference droplet and the sequence of test droplet(s) to flow through the microfluidic reaction channel; h) measuring the time of flow of the second reference droplet through the measurement section at the presence of the sequence of test droplet(s) in the microfluidic reaction channel; i) calculating the hydrodynamic resistance of the first reference droplet and the second reference droplet being followed by the sequence of the test droplet(s), on the basis of the obtained results of the time of flow form the steps: e and h; and j) determining agglutination of the biological liquid by comparing the calculated value of hydrodynamic resistance of the first reference droplet with the calculated value of hydrodynamic resistance of the second reference droplet, wherein the agglutination occurs in the sequence of test droplet(s) if the value of calculated hydrodynamic resistance of the second reference droplet is increased comparing to the value of calculated hydrodynamic resistance of the first reference droplet. a) calibrating the microfluidic device by calculating a calibrated value of hydrodynamic resistance of a sequence of droplets of a known biological liquid in which agglutination occurred and a calibrated value of a sequence of droplets of a known biological liquid in which agglutination did not occur, according to steps (b)-(i) which are then performed for a tested biological liquid; b) filling the microfluidic reaction channel with a hydrophobic continuous liquid phase, the microfluidic reaction channel having detectors (6, 7) spaced at the distance defining measurement section of the microfluidic reaction channel, wherein the pressure inducing the flow in microfluidic reaction channel constitutes the difference in pressure over the reservoir with the continuous phase and the atmospheric pressure; c) introducing into the microfluidic reaction channel a first reference droplet being a droplet of the biological liquid merged with saline or PBS or water and immiscible with the continuous phase; d) causing the first reference droplet to flow through the microfluidic reaction channel having a measurement section; e) measuring the time of flow of the first reference droplet through the measurement section of the microfluidic reaction channel; f) introducing into the microfluidic reaction channel a second reference droplet being the same as the first reference droplet, followed by a sequence of 1 to 1000 test droplet(s), the test droplet(s) being droplet(s) of the biological liquid, the same as comprised in reference droplets, and the agglutination reagent and immiscible with continuous phase; g) causing the second reference droplet and the sequence of test droplet(s) to flow through the microfluidic reaction channel; h) measuring the time of flow of the second reference droplet through the measurement section at the presence of the sequence of test droplet(s) in the microfluidic reaction channel; i) calculating the hydrodynamic resistance of the first reference droplet and the second reference droplet being followed by the sequence of the test droplet(s), on the basis of the obtained results of the time of flow form the steps: e and h; and j) determining agglutination of the biological liquid by comparing the calculated value of hydrodynamic resistance of the first reference droplet with the calculated value of hydrodynamic resistance of the second reference droplet, wherein the agglutination occurs in the sequence of test droplet(s) if the value of calculated hydrodynamic resistance of the second reference droplet is increased comparing to the value of calculated hydrodynamic resistance of the first reference droplet.