A device for detecting analytes in samples, comprising: (a) n light source units generating light, said n light source units comprising at least a first light source unit and a second light source unit ; (b) a reaction strip including (i) a test area illuminated with the light from a light source unit and including a material reacting to the analytes, (ii) a control area illuminated with the light from a light source unit and including a control material, and (iii) a background area illuminated with the light from a light source unit , in which - the test area , the background area and the control area are arranged in this order along a first direction of the test strip, - the first light source unit is arranged in the first direction at a position between the test area and the background area to illuminate the test area and the background area with light from the first light source unit and - the second light source unit is arranged in the first direction at a position between the background area and the control area to illuminate the control area and the background area with light from the second light source unit , such that the test area and the control area share the background area; and (c) at least n + 1 light receiving units arranged to one to one correspond to the test area , the control area , and the background area , respectively, for detecting light emitted from the test area , the control area , and the background area of the reaction strip, respectively. (a) n light source units generating light, said n light source units comprising at least a first light source unit and a second light source unit ; (b) a reaction strip including (i) a test area illuminated with the light from a light source unit and including a material reacting to the analytes, (ii) a control area illuminated with the light from a light source unit and including a control material, and (iii) a background area illuminated with the light from a light source unit , in which - the test area , the background area and the control area are arranged in this order along a first direction of the test strip, - the first light source unit is arranged in the first direction at a position between the test area and the background area to illuminate the test area and the background area with light from the first light source unit and - the second light source unit is arranged in the first direction at a position between the background area and the control area to illuminate the control area and the background area with light from the second light source unit , such that the test area and the control area share the background area; and (i) a test area illuminated with the light from a light source unit and including a material reacting to the analytes, (ii) a control area illuminated with the light from a light source unit and including a control material, and (iii) a background area illuminated with the light from a light source unit , - the test area , the background area and the control area are arranged in this order along a first direction of the test strip, - the first light source unit is arranged in the first direction at a position between the test area and the background area to illuminate the test area and the background area with light from the first light source unit and - the second light source unit is arranged in the first direction at a position between the background area and the control area to illuminate the control area and the background area with light from the second light source unit , such that the test area and the control area share the background area; and (c) at least n + 1 light receiving units arranged to one to one correspond to the test area , the control area , and the background area , respectively, for detecting light emitted from the test area , the control area , and the background area of the reaction strip, respectively. <EOS>