A novel low-cost approach for the semi-quantitative analysis of carbohydrate-deficient transferrin (CDT) based on fluorescence resonance energy transfer (FRET).

Background and Aim: The increase of the carbohydrate-deficient transferrin (CDT) as results of an heavy intake of alcohol for at least two weeks, is a well-known biochemical modification since the middle '70s. Notwithstanding the first commercial kit for the diagnosis of chronic alcohol abuse based on this biomarker was commercially accessible already thirty years ago, only expensive analytical methods are currently available for its determination. The present paper shows a new approach intrinsically sensitive and specific, based on a specific derivatization of transferrin, and not requiring sophisticated instrumentation.
Methods: The proposed procedure is based on a selective chelation of terbium (III) by transferrin followed by detection using an characteristic Fluorescence Resonance Transfer Energy (FRET) phenomenon (ex 298 nm - em 550 nm).
Results: The proposed procedure showed a limit of detection of 2.5 pmol/mL and a reproducibility intra-day and inter-days <15% and 20%, respectively. The results obtained analyzing 40 serum samples using the developed method, were compared with those obtained with HPLC-Vis and an R ²  = 0.8854 was found.
Conclusions: Considering its main features (low-cost, ease of operation, minimum need of instrumentation) the present method is suitable for application in screening contexts and in non-strictly regulated environments (e.g. clinical diagnosis) as well as in developing countries or remote areas.
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