The invention relates to a device for measuring fluorescent radiation emitted by biological substances, comprising a light source, a capturing unit, an evaluation unit, at least one emission fiber, and at least one detection fiber. Said emission fiber guides excitation radiation to the biological substrate and the detection fiber receives fluorescent radiation and guides it to the evaluation unit. The capturing unit comprises a semiconductor sensor arrangement that detects fluorescent radiation emitted by the biological substance in wave length areas that are separate from each other, are arranged. Data sets of at least two different reference measurements on at least two different biological substances are stored and compared to the measured measurement values to the stored data sets and issues a result relating to the pathological attacks of the examined biological substances and/or relating to the type of examined, biological substances.