A mains electricity (AC-powered) laboratory instrument intended to be used for the qualitative and/or quantitative determination of the osmotic concentration of a clinical specimen (e.g., urine, serum) by comparing its freezing-point depression curve, or vapour-pressure depression curve, with that of a standard solution. It is often used to assess an abnormal osmolar ratio which may indicate disease [e.g., renal disease, diabetes insipidus, secretion of abnormal levels of antidiuretic hormone (ADH)]. The device operates with reduced technician involvement and automation of some, but not all, procedural steps.