This present invention relates generally to devices, systems, and methods for performing optical and electrochemical assays and, more particularly, to devices and systems having universal channel circuitry configured to perform optical and electrochemical assays, and methods of performing the optical and electrochemical assays using the universal channel circuitry. The universal channel circuitry is circuitry that has electronic switching capabilities such that any contact pin, and thus any sensor contact pad in a testing device, can be connected to one or more channels capable of taking on one or more measurement modes or configurations (e.g., an amperometric measurement mode or a current drive mode).