Automation of o-dianisidine assay for ceruloplasmin activity analyses: usefulness of investigation in Wilson’s disease and in hepatic encephalopathy
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Ceruloplasmin (Cp) is a serum ferroxidase that plays an essential role in iron metabolism. It is routinely tested by immunoturbidimetric assays that quantify the concentration of the protein both in its active and inactive forms. Cp activity is generally analyzed manually; the process is time-consuming, has a limited repeatability, and is not suitable for a clinical setting. To overcome these inconveniences, we have set the automation of the o-dianisidine Cp activity assay on a Cobas Mira Plus apparatus. The automation was rapid and repeatable, and the data were provided in terms of IU/L. The assay was adapted for human sera and showed a good precision [coefficient of variation (CV) 3.7 %] and low limit of detection (LoD 11.58 IU/L). The simultaneous analysis of Cp concentration and activity in the same run allowed us to calculate the Cp-specific activity that provides a better index of the overall Cp status. To test the usefulness of this automation, we tested this assay on 104 healthy volunteers and 36 patients with Wilson’s disease, hepatic encephalopathy, and chronic liver disease. Cp activity and specific activity distinguished better patients between groups with respect to Cp concentration alone, and providing support for the clinical investigation of neurological diseases in which liver failure is one of the clinical hallmarks.
KeywordsCeruloplasmin Ceruloplasmin activity Wilson’s disease Hepatic diseases Neurodegenerative diseases Hepatic encephalopathy
Chronic liver disease
Hepatitis C virus
Coefficient of variation
Limit of detection
Limit of blank
The authors thank Dr.Vernieri F., Dr. Altamura, C. (Department of Neurology) and Dr. Vespasiani Gentilucci U., Dr. Picardi A. (Department of Clinical Medicine and Hepatology) of University Campus Bio-Medico of Rome, Italy, for providing the samples. This study was partially supported by the Grant: Italian Health Department: “Profilo Biologico e Genetico della Disfunzione dei Metalli nella Malattia di Alzheimer e nel ‘Mild Cognitive Impairment” [RF 2006 conv.58].
- Burtis CA, Ashwood ER, Bruns DE (2012) Tietz textbook of clinical chemistry and molecular diagnostics. Elsevier, NetherlandsGoogle Scholar
- Ferenci P, Lockwood A, Mullen K, Tarter R, Weissenborn K, Blei A (2002) Hepatic encephalopathy––definition, nomenclature, diagnosis, and quantification: final report of the working party at the 11th World Congresses of Gastroenterology, Vienna, 1998. Hepatology 35(3):716–721PubMedCrossRefGoogle Scholar