The invention relates to a measuring arrangement having a mobile spectrometer device which comprises a measuring head structure, wherein the measuring head structure is designed in such a way that, to carry out the spectrometric measurement, it can be placed on a portion of tissue, and a socket element which forms an inner receiving space into which the measuring head structure can be inserted, wherein a calibrating medium, produced from an opaque material, is arranged in a bottom region bounding the inner receiving space, and the socket element and the measuring head structure are designed such that, after the measuring head structure has been introduced into the socket element, the calibrating medium is sealed off in a light-tight manner from the surroundings.
