Evaluation of the clinical chemistry analyser Olympus AU400

The Olympus AU400 analyser (Olympus, Tokyo, Japan) is an automated chemistr y instrument for turbidimetric, spectrophotometric and ion selective electr ode measurements. Overall analytical performances of the AU400 and the reag ents provided by Olympus were evaluated according to the French Society of Clinical Biology guidelines. Twenty parameters including specific proteins, substrates, enzyme activities and electrolytes were tested. The linearity exceeded the specifications given by the manufacturer. Within- and between- run imprecision (CV%), evaluated at two levels, was below 1.5% for ion sele ctive electrode parameters and 3% for other analytes, except for CO2, alkal ine phosphatase at low levels and magnesium. Results compared well with tho se obtained with the analysers routinely used in our laboratory (Behring BN II, Olympus AU800 and Beckman CX3 Delta). The usual positive interferences from lipaemia and haemoglobin on total protein measurement were observed. C reatine kinase and alkaline phosphatase assays were the subject of positive and negative interference by haemoglobin, respectively. There was a negati ve interference by bilirubin in the uric acid, aspartate-amino transferase, creatine kinase and lactate dehydrogenase assays and a positive interferen ce in the calcium assay. The system was found to be very easy to use and th e workstation is user-friendly.