Cartridges and related systems and methods are disclosed. In accordance with an implementation, a method includes securing a sample container in a sample container receptacle of a cartridge using a sample container lock and coupling the cartridge to a cartridge receptacle of a system. The method also includes depositing a sample from the sample container within a sample well of the cartridge and determining a presence of a target molecule within the sample using the system. In response to the target molecule being present within the sample, the method includes releasing the sample container lock of the cartridge to allow the sample container to be removed from the sample container receptacle and for the cartridge to remain coupled to the system.