Disclosed is a drug-delivery cassette for use with a drug delivery device. The cassette includes a main board and a luer site base portion connected to the main board for positioning a luer on the main board. A drip chamber is included on the main board to collect any drug that exits the luer when the luer is attached to the luer site portion. A deflectable sensor beam is positioned to detect the presence or absence of a luer in the luer site base portion. The drug-delivery cassette further includes a drug vial spike attachable to and detachable from the cassette main board that is connected to the luer by way of a drug delivery tube.