An electrically-powered automated or semi-automated laboratory instrument intended to be used to test donor blood or tissue specimens to determine suitability for transfusion or transplantation. Testing performed may include determination of ABO, Rhesus and/or other red cell blood group systems, red cell antibody screening/identification, and/or detecting the presence of one or multiple transmissible infectious diseases. Methodology may include microplate-based serological methods, microarray, cassette or column agglutinating technology for blood group testing, and serology or nucleic acid technology for infectious disease testing.