Filter instrument, kit and method for pretreating a sample

A kit for pretreating a sample for a test of the sample, comprising:

• a filter instrument for filtering the sample,
• a plunger to push the sample through the filter instrument, and
• at least one of the following features:
• the filter instrument comprising a housing and a filter arrangement within the housing, wherein the filter arrangement comprises a sorption filter for separation of biopolymers, a filter element, and at least two securing elements located at different positions within the housing to hold the filter arrangement, or
• the plunger comprising a stop to prevent complete insertion of the plunger into the filter instrument.

A method for pretreating a sample for testing of the sample within a cartridge, comprising the steps of:

• analyzing the sample by means of a treatment agent in order to obtain a lysate,
• inserting the lysate into a filter instrument, and
• pushing the lysate through a filter arrangement arranged in the filter instrument by means of a plunger,
• filtering the lysate and separating nucleic acids from other biopolymers within the filter arrangement, and
• securing the axial position of the plunger relative to the filter instrument after insertion of the plunger into the filter instrument.