Abstract: Customization of a universal reagent cartridge with a lyophilized target-specific PCR component reagent is disclosed. The universal reagent cartridge includes multiple chambers populated with predetermined non-target-specific reagents therein. A custom reagent storage device that stores a lyophilized, target-specific reagent is provided and is configured to be end user insertable into the universal reagent cartridge to customize the universal reagent cartridge with the target-specific reagent.