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LAB
NEWS Chairman: Peter Jatlow, M.D. Editors: Edward L. Snyder, M.D.; Petrie M. Rainey, M.D., Ph.D. Production Assistant: Terri M. Fiondella Contributors: Peter Marone, MT (ASCP), MBA; Petrie Rainey, M.D., Ph.D.; Henry M. Rinder, M.D.; Brian Smith, M.D. CERULOPLASMINCeruloplasmin is a copper-carrying protein and enzyme with several physiological roles, including transport of dietary copper and facilitation of iron incorporation into transferrin. It may also serve as an antioxidant. It becomes elevated in hepatitis, hepatic obstruction, pregnancy, and as an acute phase reactant. Ceruloplasmin is also elevated in patients who use oral contraceptives. The primary indication for measuring ceruloplasmin is as a screening test for the diagnosis of Wilson's Disease (hepatolenticular degeneration). In this disorder, which is characterized clinically by abnormal copper metabolism with deposition of copper in liver, brain, cornea and kidneys, the ceruloplasmin level is depressed below the reference range (26-70 mg/dL) and usually below 20 mg/dL. However, it should be recognized that a low ceruloplasmin level is not the primary biochemical defect in Wilson's disease. Some patients (up to 5%) with clinical Wilson's disease have normal levels of the enzyme. In addition, very low levels of ceruloplasmin are observed in 10-20% of hetero-zygotes as well as some patients with nephrotic syndrome, sprue, and severe hepatic failure, none of whom show the clinical abnormalities of Wilson's disease. Patients with Menke's (kinky hair) syndrome have low ceruloplasmin levels. Neonates are also reported to have lower levels than adults. Thus, diagnosis must rest on a compatible clinical picture combined with this and other useful tests (including a low serum copper and increased urinary excretion of copper, as well as elevated copper in direct liver biopsy measurements).Previously, ceruloplasmin was measured in the Chemistry laboratory by a functional assay that relied on the ability of ceruloplasmin to catalyze the oxidation of phenylenediamine. Since June, 1996, this analyte has been measured in the Immunology Laboratory by an antigenic assay. The reference range is 26 - 70 mg/dL. Ordering on CCSS will not change. For questions, call the Immunology Laboratory at 785-2440. References
Brian Smith, M.D.; Petrie Rainey, M.D., Ph.D. |
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