Capillary Electrophoresis (CE) vs. HPLC in the determination of asialo-Tf, a crucial marker for the reliable interpretation of questioned CDT increases.

BACKGROUND AND AIM: CDT is a collective biomarker including asialo- and disialo-Tf, but researchers have generally focused attention on disialo-Tf, because of its easier detectability, since asialo-Tf is typically not detectable by the current methods in abstinent individuals, social drinkers and in many alcohol abusers with moderate CDT increases. In the search of a confirmation marker of alcohol-related CDT increases, the detectability of asialo-Tf was re-evaluated comparatively by using CE vs. HPLC. METHODS: 468 serum samples compulsorily drawn in a forensic/administrative context were analyzed by CE and HPLC to compare their sensitivity towards asialo-Tf. RESULTS: CE allowed the identification of asialo-Tf in 108 out of 165 CDT "positive" cases, based on disialo-Tf measurement (cut-off 1.8%). HPLC showed a detectable asialo-Tf peak only in 2 cases. In addition, in some cases of disputed CDT increases, the quasi-absence of this Tf component in front of an important increase of disialo-Tf allowed the ruling out of a diagnosis of alcohol abuse, in agreement with all other clinical and laboratory data. CONCLUSIONS: The present work shows a superior performance of CE vs. HPLC for the determination of asialo-Tf and the importance of this CDT component to avoid misinterpretation of non-alcohol related CDT increases.

A new sample treatment for asialo-Tf determination with capillary electrophoresis: an added value to the analysis of CDT.

BACKGROUND AND AIM: The non-glycosylated glycoform of transferrin (Tf), known as asialo-Tf, was not selected (in favor of disialo-Tf) as the measurand for the standardization of carbohydrate deficient transferrin (CDT) determination because of a lower diagnostic sensitivity provided with the currently available analytical procedures for sera. However, asialo-Tf could provide an additional value to disialo-Tf in the CDT analysis employed in forensic toxicology contexts. The present work aimed at developing an easy sample preparation based on PEG precipitation in order to improve the detectability of asialo-Tf in capillary electrophoresis (CE). METHODS: Equal volumes (35 µL) of serum and of 30% PEG-8000 were mixed and briefly vortexed. After centrifugation, the supernatant was iron saturated with a ferric solution (1:1, v/v). The mixture was analyzed in CE for asialo-Tf and disialo-Tf determination. RESULTS: PEG-8000 precipitation allowed the improvement of the baseline in the electropherograms in terms of interferences reduction particularly in the asialo-Tf migration region. The detection of asialo-Tf was possible in 89% of samples with disialo-Tf above the cut-off limit, whereas only 16% of them showed asialo-Tf by employing the traditional sample preteatment. CONCLUSIONS: Asialo-Tf represents an additional value to disialo-Tf as a biomarker of alcohol abuse in forensic toxicology.