Described herein are various inventions and embodiments thereof, directed to systems, devices, and methods for analysis of a biofluid, as well as controlling a biofluid analysis system using a microfluidic device. Embodiments of biofluid analysis systems disclosed herein may provide analysis of a biofluid to identify and characterize one or more analytes. An apparatus may include a first layer defining a first opening and a second opening. The first layer may be substantially transparent. A second layer may be coupled to the first layer and define a microfluidic channel that establishes a fluid communication path between the first opening and the second opening. At least a portion of the second layer may be substantially opaque.