Serum carbohydrate-deficient transferrin: mechanism of increase after chronic alcohol intake

Evaluation of carbohydrate-deficient transferrin measurements on the V8 capillary electrophoresis system and comparison with the IFCC approved HPLC reference method and N-Latex immunonephelometric assay

OBJECTIVES

Carbohydrate-deficient transferrin (CDT) measurements are commonly used for the identification and follow-up of individuals suspected of chronic alcohol abuse. This study describes the analytical characteristics of the CDT assay on the Helena Biosciences V8 electrophoresis analyzer and compares its diagnostic performance to the International Federation of Clinical Chemistry and Laboratory Medicine approved high performance liquid chromatography (HPLC) method and the N-Latex CDT immunonephelometric assay.

METHODS

The analytical performance of the V8 assay, including the linearity and the imprecision, was studied at two separate locations. Method comparison analysis was performed by studying the correlation, bias and agreement between the V8, HPLC and the N-Latex assays in 231 patient samples.

RESULTS

The total imprecision ranged between 5.1 and 24.3% and was ≤13.1% for samples with concentrations above the clinical cut-off value (≥1.62%). The method comparisons revealed excellent correlations with r²≥0.97 for all comparisons. Measurements on the V8 showed a bias of -0.83 (-22.24%) and -0.40 (-12.26%) with the HPLC and N-Latex assays, respectively. The assays showed excellent agreements (Kappa scores ≥ 0.8) in classifying subjects with elevated CDT values. Receiver operating characteristic (ROC)-curve analysis, using the HPLC classification as reference, revealed areas under the ROC-curves of 0.981 (95% CI, 0.97-0.99) and 0.996 (0.99-1.00) for the N-Latex and V8 assays, respectively.

CONCLUSIONS

CDT measurements on the V8 assay are highly correlated with both the HPLC and the N-Latex assay and show excellent agreement in classifying subjects with elevated CDT values. Overall, the V8 CDT analysis is a robust, reliable and effective method to measure CDT concentrations in serum samples.

Altered glycomics in liver disease

Chronic liver diseases are a serious health problem worldwide. The biosynthesis of proteins takes place in the liver, and protein glycosylation is the most common form of post-translational modification of proteins, with as many as 70% of all human proteins estimated to contain one or more glycan chains. Protein glycosylation is the enzymatic addition of sugars or oligosaccharides to proteins, which increases the diversity of the proteome to a level unmatched by any other post-translational modifications because of the various aspects of modification, including glycosidic bond, glycan composition, glycan structure, and glycan length. Changes in the glycan structures of proteins are an indication for liver damage, which plays an important role in the pathogenesis and progression of various liver diseases. The aim of this paper is to give an overview of the altered protein glycosylation in different etiologies of hepatitis, liver fibrosis/cirrhosis, hepatocellular carcinoma, alcoholic and fatty liver diseases based on the analysis of serum and saliva using the glycomics technology.