A Proof-of-concept Analysis of Carbohydrate-deficient Transferrin by Imaged Capillary Isoelectric Focusing and In-capillary Immunodetection

Carbohydrate-deficient transferrin (CDT) is a reliable biomarker for chronic alcohol abuse. We developed a method for CDT analysis by capillary isoelectric focusing, followed by immunodetection directly in the capillary, in an automated fashion and on a single platform (Peggy Sue™; ProteinSimple, CA, USA). Transferrin glycoforms in serum samples, including disialo-transferrin, were separated and their apparent isoelectric points and relative percentages were determined. The relative CDT values (percent of total transferrin) matched expected values for both healthy and alcoholic samples. Because the method leveraged the sensitivity of an immunoassay, CDT was measured when serum samples were diluted up to 1200-fold, reducing the volume of serum required. Finally, the process is fully automated, with up to 96 samples analyzed per batch.