A mains electricity (AC-powered) laboratory instrument intended to be used for the qualitative and/or quantitative in vitro determination of chemical and/or biological markers (e.g., drug, hormone, microbial toxin) in a clinical specimen, using an immunological method that utilizes a chemiluminescent detection system together with sample processing, data processing and/or data display software. The device operates with minimal technician involvement and complete automation of all procedural steps.