A portable testing device includes a housing with an integrated touchscreen display and a receptacle in which a sample holder containing a biological sample and reagent mixture can be placed. The portable testing device further includes an optical assembly positioned in the housing, an electronic assembly that is configured to receive data from the optical assembly and transmit it for display on the touchscreen display, and a power supply in the housing to power the portable testing device. The optical assembly includes an excitation filter that extends across the entire optical assembly and an emission filter that extends across the entire optical assembly.