Test set for a photometric measuring device and photometric measuring method for a sample liquid

A test set for a photometric measuring device, comprising

• a mixing container which defines a filling opening and which receives a first fluid in an interior thereof, and a closing element which is removable from the filling opening;
• and
• a dosing container which is insertable in a sealing manner in the filling opening of the mixing container and which contains a second fluid in a sealed hollow chamber which is sealed on one side by a displaceable sealing plunger and on an opposite side by a movable plug, wherein the dosing container comprises an integrated sample-taking device which, after the insertion of the dosing container in the filling opening of the mixing container, contacts the first fluid present in the mixing container, wherein the sample-taking device comprises a capillary which is open on both sides and whose volume is preferably between 5 μl and 50 μl.