Influence of physical properties of cuvette surface on measurement of serum lipase

Despite striking similarities among colorimetric lipase assay recipes, marked intervendor differences are noted in the reported lipase values. In the present study, the effect of physical properties of the cuvette surface on measurement of serum lipase was investigated. Lipase activity was measured concomitantly in cuvettes from three different analyzers: Vista (Siemens), Modular (Roche), and Synchron (Beckman Coulter). The surface/volume ratio of the cuvettes and the contact angle of the cuvette polymers were determined. The effects of various characteristics of serum (biochemical parameters, surface tension) were also examined. Serum lipase activities based on the colorimetric methylresorufin assay differed markedly according to the cuvettes used. More specifically, in the lower activity rate, marked differences were reported. The physical properties of the various cuvettes showed remarkable differences, especially in the contact angles. Other biochemical parameters (bilirubin, alkaline phosphatase, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides) and serum surface tension did not affect the results. Serum lipase activity is affected by the physical properties of the cuvette surface.