Abstract: A diagnostic testing device is disclosed. The testing device includes a base member and a cover member which defines an opening for the reception of a liquid specimen. A distribution wheel delivers portions of the specimen to antibiotic units which are circumferentially spaced. Indicator units are in communication with the cover member. A delivery cylinder extends upwardly from each of the antibiotic units toward a respective one of the indicator units. Relative vertical movement between the delivery cylinder and the indicator unit places the cylinder and the indicator unit into an engaging relationship. A change in coloration at an indicator unit indicates a positive reaction.