PURPOSE: Wilson's disease is an autosomal recessive disorder characterized by copper accumulation in the liver, brain, and other organs due to defected copper metabolism. The incidence of Wilson's disease is approximately one in 30,000 population in the world, more common than phenylketonuria in Korea. The early diagnosis or presymptomatic diagnosis of Wilson's disease is critical in order for them to live a normal life. However, unfortunately, there are no commercial kits available for Wilson's disease screening in the world yet. METHODS: We developed a mass-screening kit for the purpose of early diagnosis and prevention of Wilson's disease using sandwich ELISA method. This kit can handle a large number of samples at the same time by using filter paper as in newborn screening. Using the polyclonal or monoclonal anti-ceruloplasmin antibodies, this kit determines the plasma ceruloplasmin levels-one of the main markers for Wilson's disease. RESULTS: The plasma levels of the ceruloplasmin were considerably lower in the Wilson's disease (4.5+/-1.6 mg/dL) group compared to normal controls(22.1+/-1.4 mg/dL), sufficient to be used for mass screening. In addition, the results using this screening kit showed 100% positive and negative concordance rates with the test results obtained from immuno-turbidimetry analysis which is the currently used in most test centers for ceruloplasmin measurement in the serum or plasma after centrifugation. CONCLUSION: Taken together, we successfully developed a screening kit which is very effective for the early diagnosis and prevention of Wilson's disease. By using simple filter paper method for sample collection, this kit provides suitable mass screening. We suggest the screening for Wilson's disease at the age of 3-5 years.