Fully automated copper measurement kit development

Clinical chemistry deals with laboratory tests performed for diagnosis and treatment follow-up of diseases. Laboratory tests performed in medicine are heavily based on automated analyzers, however, analysis of many analytes have not yet been adapted to automated systems. For analysis of copper in biological fluids, AAS, a non-automated and not easily available technique is widely used. AAS is a technique that is not easy-to-perform and readily available in most hospital's routine clinical chemistry laboratory. Therefore, samples are transported to outside laboratories for copper measurement. This transport increases the costs and causes a delay in report of results to the requesting physician. Quick and easy analysis and follow-up of levels of trace elements is important. These elements carry very important roles in function and structure of key enzymes in important metabolic pathways. Copper plays key roles in many metabolic events such as iron metabolism, cellular respiration, free radical detoxification, synthesis of connective tissue elements and neurotransmitters, and neuronal signaling. Disorders of copper metabolism result in diseases with devastating clinical findings in case of deficiency and accumulation of copper. In this study, development and perfromance evaluations of a new reliable and stable automated clinical chmeistry method for copper measurement was aimed as an alternative to AAS and unstable and unreliable colorimetric techniques. Automated spectrophotometry techniques were used for this purpose. New reactives were developed and the performance of the new technique was analyzed for suitability in clinical use. CV% was lower than 2, bias was between -1 and 1. 0.96 correlation was observed with AAS. R2 was 0.95 on regression analysis. LoB 0.178 μg/dl, LoD 0.607 μg/dl, LoQ 3.207 μg/dl were observed. Total analytical error was 1.89, sigma was 3.62, combined measurement uncertainty was 2.87 while expanded measurement uncertainty was 5.74. The method is linear between 4-1000 μg/dl. No carry-over effect was observed. No interference with zinc, magnesium, cobalt and iron ions were observed. Shelf-life is at least 6 months, and on-board stability was at least 25 days. Reference interval is 91-185 μg/dl. The method is suitable for clinical use. A new method with performance suitable for global standards and producible in Turkey is developed. Keywords: copper, automated analyzers, colorimetry, performance evaluation