Abstract: A test strip is provided for visually indicating the effectiveness of selected antibiotics, bactericidal drugs, or the like in combatting microorganisms in specimens taken from a patient. The test strip comprises a porous, water absorbent or adsorbent body which may be made of plastic foam material, upon the porous surface of which spaced stripes of testing material are applied by automatic printing or coating apparatus. One of the stripes contains a nutrient substrate for the tested microorganisms and the other stripes contain a mixture of the same nutrient substrate and various selected bactericidal and bacteristatic drugs. The test strip is initially manufactured as a strip of long length with the stripes extending longitudinally thereon, and is then separated into short transverse panels for use in the testing. Moisture barriers are formed between the stripes by the application of pressure or heat to the porous surface of the test strip.