An apparatus is described for identifying the patient and marking the laboratory test tubes associated with said patient during the sampling of biological material to be analysed, comprising a high-security portable hardware device (1) for processing and storing the patient's data, a device (2) for reading said portable hardware device and for the biometric identification of the patient, a personal computer (4) interacting with an operator and connected to a computer network for exchanging data by means of an application software with a remote means (3) for storing data. Said apparatus also includes a computerised test tube labelling unit (5) comprising a printer (8) for printing bar codes on labels (7) able to receive print commands from said personal computer (4) following a comparison between expected and detected test tubes housed in a positioning and identification device (9) supported by said labelling unit (5).