These test strips can be considered as a mobile laboratory on a few square millimeters of plastic strip. As a screening method they provide the user with a rapid overview of the situation, which helps in making the choice of what, and perhaps if, further analysis is required, thereby leading to potentially substantial savings in time and analytical resources. The strip is a biologically-degradable polyester foil and the low reagent content, in the reaction zones, assists problem-free waste disposal.