The Serosonic system (Serosonic Laboratories, St. Louis) is a complete system for biochemical analyses. It consists of a colorimeter with built-in dry baths pre-set at 37°C and 100°C, and a centrifuge. Kits are available for several types of test. These contain reagents dispensed into disposable glass cuvettes, pipettes with disposable tips, and mixi-tubes which are mixing vials. Twelve biochemical tests (albumin, total protein, cholesterol, glucose, uric acid, amylase, alkaline phosphatase, lactate dehydrogenase, alanine aminotransferase, bilirubin, creatinine and blood urea nitrogen) were assessed for accuracy and precision. Comparison with manual methods in this laboratory and with commercial control sera indicate that the Serosonic system can be made reliable. It is necessary to ensure that faulty reagent vials are detected and discarded. The Serosonic system is suitable for routine and emergency work and for rapid checks of results.