The present invention relates to a device (10) for use in fluid sample analysis. It is described to position (310) a top part (20) of the device (10) adjacent to a base part (30) of the device so as to define a fluidic receiving region in between, the top part being provided with a through opening fluidly connected to the fluidic receiving region, and the bottom part being provided with a radiation window adjacent to the fluidic receiving region. A fluidic sample is supplied (320) through the opening (24). The fluidic sample is moved laterally (330) in the fluid receiving region without the use of an intermediary membrane between the top part and the base part. A radiation is emitted (340) to the fluid receiving region. A radiation is detected (350) that is reflected by the device. A presence of the fluidic sample is determined (360) on the basis of a measured reflectance value based on the detected radiation.