Microfluidic detection system and a microfluidic cartridge

A microfluidic detection system comprising a microfluidic cartridge and a detector assembly,

• the microfluidic cartridge comprises a first and a second side and at least one flow channel and an inlet to the at least one flow channel for feeding a liquid sample, the at least one flow channel comprises a plurality of first optical detection sites, and
• the detector assembly comprises a slot for inserting the microfluidic cartridge and a first fixed light source with a beam path and an optical reader for reading out optical signals from at least one of said first optical detection sites, said detector assembly and the microfluidic cartridge are constructed such that when the microfluidic cartridge is inserted to a first predetermined position into said slot, one of said first optical detection sites of the microfluidic cartridge is positioned in the beam path of the first light source, and when the cartridge is inserted to a second predetermined position into said slot, another one of the first optical detection sites of the microfluidic cartridge is positioned in the beam path of the first light source, wherein each of said first and said second predetermined positions of said microfluidic cartridge into said slot are determined by projecting flanges arranged on the microfluidic cartridge and cavities arranged on the detector assembly at selected positions or projecting flanges arranged on the detector assembly and cavities arranged on the microfluidic cartridge at the selected positions, which engage or snap into place to temporarily position the microfluidic cartridge in the detector assembly at one of the first and the second predetermined positions, said projecting flanges and cavities comprises a first set of projecting flanges and cavities which correspond to the first predetermined position and said projecting flanges and cavities comprises a second set of projecting flanges and cavities which correspond to the second predetermined position.