Abstract: Invention describes a method and a device for testing toxicity of a test sample. The method comprises at least the steps of: providing an aliquot or a volume of light producing test reagent liquid in a reagent vial, moistening a control swab with the light producing test reagent liquid, moistening a test swab with the test sample, moistening the test swab with the light producing test reagent liquid, reading luminescence of the control swab in a luminometer and thereby obtaining a luminescence value of a control sample, reading luminescence of the test swab in the luminometer and obtaining a luminescence value of the test sample, calculating the toxicity of the test sample by comparing the luminescence value of the control sample to the luminescence value of the test sample. According to the invention the moistenings of the control swab and the test swab with the light producing test reagent liquid are done with the same aliquot of light producing test reagent liquid in the same reagent vial.