AUTOMATIC SCANNING APPARATUS FOR PERFORMING OPTICAL DENSITY TESTS ON LIQUID SAMPLES, METHOD FOR TESTING FOR ANTIBIOTIC SUSCEPTIBILITY, AND METHOD FOR IDENTIFYING MICROORGANISMS

AUTOMATIC SCANNING APPARATUS FOR PERFORMING OPTICAL DENSITY TESTS ON LIQUID SAMPLES, METHOD FOR TESTING FOR ANTIBIOTIC SUSCEPTIBILITY, AND METHOD FOR IDENTIFYING MICROORGANISMS Apparatus is provided for automatically scanning electronically each well of a multi-well tray containing many liquid samples. A light source, preferably a single source, is passed through the wells to an array of photosensitive cells, one for each well. There is also a calibrating or comparison cell receiving the light. Electronic apparatus reads each cell in sequence, quickly completing the scan without physical movement of any parts. The resultant signals are compared with the signal from the comparison cell and with other signals or stored data and determinations are made and displayed or printed out. Thereby, and by the methods of the invention, such matters as minimum inhibitory concentrations (MIC) of drugs and identification of microorganisms are achieved.