Disclosed is a process for in vitro detection of an infection by a dengue virus in an individual, including the following steps: contacting a blood sample from the individual with a ligand specific to the NS1 protein of said dengue virus, to capture NS1 protein if it is present in the blood sample, said ligand being immobilized on a solid support; detecting the presence of NS1 protein via a mass spectrometry reading; and if NS1 protein is detected, concluding that the individual has been infected by dengue virus.