Analysis of serum ceruloplasmin levels in wilson disease.

ABSTRACT

C Nisarat Opartkiattikul, M.D. Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand. Siriraj Med J 2006;58 610 E-journal http// www.sirirajmedj.com eruloplasmin is copper-containing protein of plasma which is synthesized mostly in the liver. Reduc tion in serum concentration of ceruloplasmin are diagnostically significant of Wilson disease Menkes disease, and nutritional copper deficiency.1 Indications for ordering ceruloplasmin are hepatitis-marker-negative liver disease in childhood or adolescence (suspected Wilson disease), neurodegenerative symptoms and signs of connective tissue disease in infants and small children (suspected Menkes disease), and hypochromic microcytic, iron-refractory anemia (suspected nutritional copper deficiency). At Siriraj Hospital, there are approximately twenty orders of ceruloplasmin level per month. Ceruloplasmin can be assayed either immunochemically (radial immunodiffusion, immunonephelometry or immunoturbidimetry) or functionally (copper oxidase activity). The latter assay measures only native, coppercontaining ceruloplasmin, whereas the formers measure both the intact molecule and, to varying degrees, apoceruloplasmin and proteolytic fragment. The oxidase activity method is more difficult to perform and less specific but it may provide better clinical information.2 Comparative analysis of serum ceruloplasmin levels in Wilson disease by oxidase activity method and immunonephelometric method reported in this study revealed a high correlation between the two methods. This result suggests for replacing the conventional oxidase activity method by immunonephelometric method which is simpler, automated and has a well accepted quality control. Even though the immunonephelometric method cannot report the ceruloplasmin result lower than 8 mg/ dL, this is of no clinical significance because the cut off level for diagnosis of Wilson disease is at 13mg/dL. REFERENCES 1. Kratz A, Lee-Lewandrowski E, Lewandrowski K. The plasma proteins. In Lewandrowski K, ed. Clinical-laboratory management and clinical correla tion. Philadelphia, Lippincott, Williams & Wilkins, 2002531-60. 2. Johnson AM, Rohlfs EM, Silverman LM. Protein. In Burtis CA, Ashwood ER, eds. Tietz Textbook of Clinical Chemistry, 3rd ed. Philadelpha, W.B.Saunders Co., 1999477-540.