NÅLEENHED OG LÆGEMIDDELFREMFØRINGSANORDNING MED EN SÅDAN NÅLEENHED

Described herein are specialized needle assemblies for injection systems. One example injection system includes a needle assembly configured to removably attach to a drug delivery device and a housing configured to receive a drug cartridge. The needle assembly includes a needle configured to extend through an outlet port of the drug delivery device and establish fluid communication with the drug cartridge within the housing of the drug delivery device. The needle assembly may include a fluid flow sensor monitoring the fluid flow and/or occlusions within the needle assembly, and provide indications of an occluded or clogged needle and/or one or more indications of proper flow through the needle, e.g., non-occlusion of the needle. In some examples, the arrangement of the needle assembly includes sensors to detect an occlusion within a portion of a needle.