Carbohydrate deficient transferrin and forensic medicine

Driving license regranting: Hair EtG, serum CDT, and the role of sociodemographic and medicolegal variables

Driving under the influence (DUI) of alcohol is a road safety problem. Driving license regranting is based on the evaluation of medicolegal and toxicological variables that may include serum carbohydrate-deficient transferrin (CDT) and hair ethyl glucuronide (hEtG). The aim of the study was to compare the diagnostic performance of CDT and hEtG in a population of DUI offenders. Other factors potentially associated with heavy alcohol use were explored. The population included DUI offenders examined during the period of January 1, 2019, through June 30, 2022. Sociodemographic, medicolegal, and toxicological variables were collected. CDT in serum and EtG in head hair were determined in all subjects. Excessive alcohol intake (hEtG ≥30 pg/mg) was considered cause for unfitness to drive. Cohen's kappa coefficient was calculated. Descriptive analyses were performed using chi-square and Mann-Whitney tests. Variables significantly different between the groups were included in a multivariate binary logistic regression model. The sample encompassed 838 subjects (case group: 179, comparison group: 689). CDT exhibited poor agreement (κ = 0.053) with hEtG as the reference test. Lower education, age at DUI, heavy smoking, and GGT levels associated with heavy alcohol consumption differentiated the two groups. For DUI offenders, the use of CDT to assess heavy alcohol consumption is limited, possibly due to the time-window assessed, the time required for normalization, and the different amount of ethanol needed to reach higher CDT levels, in comparison to hEtG; thus, hEtG assessment is strongly recommended for this population. Heavy smoking, GGT, education, and age could be related to heavy alcohol consumption and higher risk of DUI.

Analytical and diagnostic aspects of carbohydrate deficient transferrin (CDT): A critical review over years 2007-2017

The need for investigating alcohol abuse by means of objective tools is worldwide accepted. Among the currently available biomarkers of chronic alcohol abuse, carbohydrate-deficient transferrin (CDT) is one of the most used indicator, mainly because of its high specificity. However, some CDT analytical and interpretation aspects are still under discussion, as witnessed by numerous research papers and reviews. The present article presents a critical review of the literature on CDT appeared in the period from 2007 to 2017 (included). The article is organized in the following sections: (1) introduction, (2) pre-analytical aspects (3) analytical aspects (4) diagnostic aspects (5) concluding remarks. As many as 139 papers appeared in the international literature and retrieved by the search engines PubMed, Web of Science and Scopus are quoted.

Infrared analysis of lipoproteins in the detection of alcohol biomarkers

Background:

Alcoholism is a major public health problem. Alcohol causes modifications in the composition and concentration of lipoproteins and influences the enzymes and transfer proteins that transform lipoproteins in plasma. Alcohol is associated with the presence of alcohol biomarkers (fatty acid ethyl esters [FAEEs] and phosphatidylethanol [PEth]) in lipoproteins. We explore the possibilities of detecting alcohol biomarkers in non-high-density-lipoproteins (non-HDLs) precipitated from serum using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR).

Methods:

Analyzes were carried out on stored serum samples, with known % carbohydrate-deficient transferrin (CDT) values, included in a driver’s license regranting program under the control of the Belgian Institute of Road Safety. The study consisted of 127 control samples (CDT≤1.3%) and 114 alcoholic samples (CDT>1.3%). Liver enzymes, CRP, triglycerides, total, HDL- and LDL-cholesterol values were determined. Non-HDLs were precipitated with sodium phosphotungstate and MgCl2 and analyzed using ATR-FTIR in the range from 4500 cm−1 to 450 cm−1 using a Perkin Elmer ATR-FTIR Spectrometer Two.

Results:

The area under the curve of the 1130–990 cm−1 region (AUC1130−990 cm−1) was able to discriminate controls from alcoholics (p<0.0001) due to the presence of FAEEs in lipoproteins. Multiple regression analysis significantly predicted the AUC1130−990 cm−1 (adj. r2=0.13, p<0.0001). Significant correlations were found between AUC1130−990 cm−1 and CDT values (r=0.32, p<0.0001), AST/ALT ratio (r=0.21, p=0.001). GGT showed no significant correlation.

Conclusions:

Infrared analysis of lipoproteins is a potential tool in the detection of alcohol biomarkers.

Classification of congenital disorders of glycosylation based on analysis of transferrin glycopeptides by capillary liquid chromatography-mass spectrometry

In this work, we describe a multivariate data analysis approach for data exploration and classification of the complex and large data sets generated to study the alteration of human transferrin (Tf) N-glycopeptides in patients with congenital disorders of glycosylation (CDG). Tf from healthy individuals and two types of CDG patients (CDG-I and CDG-II) is purified by immunoextraction from serum samples before trypsin digestion and separation by capillary liquid chromatography mass spectrometry (CapLC-MS). Following a targeted data analysis approach, partial least squares discriminant analysis (PLS-DA) is applied to the relative abundance of Tf glycopeptide glycoforms obtained after integration of the extracted ion chromatograms of the different samples. The performance of PLS-DA for classification of the different samples and for providing a novel insight into Tf glycopeptide glycoforms alteration in CDGs is demonstrated. Only six out of fourteen of the detected glycoforms are enough for an accurate classification. This small glycoform set may be considered a sensitive and specific novel biomarker panel for CDGs.

Capillary Electrophoresis Method for the Assessment of Erythropoiesis-Stimulating Agents in Final Formulations

Capillary electrophoresis (CE) comprises several separation modes that can be used to characterize proteins in terms of physico-chemical properties such as isoelectric point or molecular weight, or in terms of purity/heterogeneity for the presence of charge or size variants. In glycoproteins the heterogeneity occurring as a consequence of variable amounts of terminal sialic acid residues on glycan moieties can be detected by CE. As such, a capillary zone electrophoresis (CZE) method was found suitable for the detection of isoforms of several erythropoiesis-stimulating agents (Bietlot and Girard, J Chromatogr A 759:177-184, 1997; Boucher et al., J Pharm Biomed Anal 71:207-213, 2012). In particular, the method can be used to analyze finished products containing erythropoietin-α, erythropoietin-β, or darbepoetin-α regardless of the formulation and without the need for sample pretreatment. The major excipients encountered in the various formulations included polysorbate 80, polysorbate 20, or human serum albumin. The ability of the method to resolve isoforms of the active ingredient in finished product enables the comparison of the isoform profile with that of the corresponding drug substance, allowing the assessment of the structural integrity and content of the active ingredients in finished products.

Carbohydrate-Deficient Transferrin Determination in a Clinical Setting: Consistency Between Capillary Electrophoresis Assays and Utility of HPLC as a Confirmatory Test

BACKGROUND

Carbohydrate-deficient transferrin (CDT) is used to assess chronic alcohol consumption in administrative and forensic context. The aim of the present study was the optimization of the diagnostic strategy for CDT determination in a clinical laboratory setting.

METHODS

Two capillary zone electrophoresis (CZE) assays, the CEofix CDT (Analis, Suarlée, Belgium) run on single capillary MDQ instrument and the muticapillary (Sebia, Lisses, France), were compared as screening methods and a commercial high-performance liquid chromatography (HPLC) assay (Recipe, Munich, Germany) was used for confirmation.

RESULTS

In total, 367 serum samples were analyzed by both CZE assays with concordant classification in 92% of cases. All discordant samples were classified as negative by HPLC, as did 2/3 of those that could not be classified by either CZE assay. Classification of samples with CDT values close to cut-off by CZE was confirmed by HPLC in 95-100% of negative samples but only in 28.6-33.3% of positive samples.

CONCLUSIONS

Both CZE assays proved suitable for CDT screening. HPLC was useful for discriminating CDT value in most of samples that could not be interpreted by CZE due to analytical interferences. Considering the implication of CDT testing, HPLC assay may also be helpful for the confirmation of positive results close to the cut-off value of CZE assays.

Usefulness of indirect alcohol biomarkers for predicting recidivism of drunk-driving among previously convicted drunk-driving offenders: results from the recidivism of alcohol-impaired driving (ROAD) study

AIM

In several European countries, drivers under the influence (DUI), suspected of chronic alcohol abuse are referred for medical and psychological examination. This study (the ROAD study, or Recidivism Of Alcohol-impaired Driving) investigated the usefulness of indirect alcohol biomarkers for predicting drunk-driving recidivism in previously convicted drunk-driving offenders.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

The ROAD study is a prospective study (2009-13) that was performed on 517 randomly selected drivers in Belgium. They were convicted for drunk-driving for which their licence was confiscated. The initial post-arrest blood samples were collected and analysed for percentage carbohydrate-deficient transferrin (%CDT), transaminsase activities [alanine amino transferase (ALT), aspartate amino transferase (AST)], gamma-glutamyltransferase (γGT) and red cell mean corpuscular volume (MCV). The observation time for each driver was 3 years and dynamic.

FINDINGS

A logistic regression analysis revealed that ln(%CDT) (P < 0.001), ln(γGT) (P < 0.01) and ln(ALT) (P < 0.05) were the best biochemical predictors of recidivism of drunk-driving. The ROAD index (which includes ln(%CDT), ln(γGT), -ln(ALT) and the sex of the driver) was calculated and had a significantly higher area under the receiver operator characteristic curve (0.71) than the individual biomarkers for drunk-driving recidivism. Drivers with a high risk of recidivating (ROAD index ≥ 25%; third tertile) could be distinguished from drivers with an intermediate risk (16% ≤ ROAD index < 25%; second tertile; P < 0.001) and a low recidivism risk (ROAD index < 16%; first tertile; P < 0.05).

CONCLUSIONS

Of all routinely used indirect alcohol markers, percentage of carbohydrate-deficient transferrin is the major predictor of recidivism of drunk-driving. The association with gamma-glutamyltransferase, alanine amino transferase and the sex of the driver could have additional value for identifying drunk-drivers at intermediate risk of recidivism. Non-specific indirect alcohol markers, such as alanine amino transferase, gamma-glutamyltransferase, aspartate amino transferase and red cell mean corpuscular volume have minimal added value to % carbohydrate-deficient transferrin for distinguishing drunk drivers with a low or high risk of recidivism.

Microheterogeneity of serum β-hexosaminidase in chronic alcohol abusers in a driver's license regranting program

BACKGROUND

Carbohydrate-deficient transferrin (CDT) is one of the best indicators for chronic alcohol abuse and detection of relapse. In this study, we explore the microheterogeneity of β-hexosaminidase (β-HEX) in chronic alcohol abusers in the framework of a driver's license regranting program. Studies have shown that increased serum activity of β-HEX B (isoforms P, I, and B) may be a sensitive marker for chronic alcohol abuse. Here, we describe methodology, limitations, and correlation of β-HEX isoforms with CDT.

METHODS

CDT was assayed at the central laboratory of the Ghent University Hospital by capillary zone electrophoresis, measured on the Capillarys 2™ system and was expressed as a percentage of total serum transferrin (%CDT). Serum of chronic alcohol abusers was compared to nonheavy drinkers using agarose gel isoelectric focusing (IEF). Total β-HEX activity was assayed fluorimetrically following preparative IEF in 81 subjects. β-HEX isoforms were investigated and compared between nonheavy drinkers and heavy drinkers.

RESULTS

Agarose gel IEF shows additional cathodal bands in serum of chronic alcohol abusers. Mean total β-HEX activity between pH 6.8 and 7.7, designated as HEX-7, showed the highest correlation with %CDT (r = 0.70, p < 0.0001, n = 68). In a selected subgroup, where CDT could not be quantified (n = 13) because of an atypical electropherogram, HEX-7 was in concordance with either estimated %CDT value or liver enzyme activities.

CONCLUSIONS

In this proof-of-concept study, we introduce a novel approach to quantify β-HEX isoforms using preparative IEF and fluorimetry. A highly significant correlation of HEX-7 and %CDT has been found. Because of exclusion of the P isoform, HEX-7 could be a useful supplementary marker for detecting chronic alcohol abuse.

Non-oxidative ethanol metabolites as a measure of alcohol intake

Recent alcohol intake can be monitored by the measurement of indirect biomarkers. Elevated levels of liver enzymes (i.e. gamma-glutamyl transferase (GGT), alanine amino transferase (ALT) and aspartate amino transferase (AST)) in blood are commonly used in clinical practice as an indicator of alcohol-induced liver damage. With the exception of carbohydrate-deficient transferrin (CDT), the specificity of indirect markers is only moderate because many cases of elevated levels are unrelated to alcohol consumption. Because of their intermediate half-life and tendency to accumulate in hair, non-oxidative ethanol metabolites can be used as markers with an intermediate timeframe between ethanol measurements and GGT and CDT with regard to recent alcohol consumption occurring between hours to 1 week. Additionally, these biomarkers offer a high ethanol-specificity in combination with approximately a two-fold higher sensitivity in comparison with indirect alcohol markers. In case of forensic use of direct ethanol metabolites, caution has to be taken in interpretation and pre-analytical pitfalls should be considered.

Alcoholic hepatitis: a clinician's guide

Alcoholic hepatitis is a frequent reason for admission and a common consultation request for hepatologists and gastroenterologists. Although it seems to occur acutely, it is usually subacute and often superimposed on underlying alcoholic cirrhosis. Typically patients have a background of drinking on a daily basis, but, in response to a life crisis, patients have started drinking massively.

Clinical performance of the carbohydrate-deficient transferrin (CDT) assay by the Sebia Capillarys2 system in case of cirrhosis. Interest of the Bio-Rad %CDT by HPLC test and Siemens N-Latex CDT kit as putative confirmatory methods

BACKGROUND

The CDT assay used to detect chronic alcohol abuse is difficult with cirrhotic patients. This article describes the performances of several CDT assays in case of cirrhosis. The CDT-Capillarys assay by capillary zone electrophoresis was used for initial testing. Two additional methods were tested as putative confirmatory methods.

METHODS

110 patients with known hepatic status had their CDT measured by the Capillarys2 or alternative methods. Self-reported alcohol intake was used to assess the performances of CDT assays.

RESULTS

Capillarys2 performance was lower in case of cirrhosis, many electropherograms displaying various abnormalities. We used the proper separation of the di- and tri-sialotransferrin peaks to select reliable profiles. This selection led to the classification of cirrhotic and non-cirrhotic patients in abusers and abstainers with similar performances. However, no interpretation was available for 54% of the cirrhotic patients and neither the BioRad %CDT by HPLC test, nor the Siemens N-Latex CDT kit was suitable as confirmatory methods for these samples.

CONCLUSIONS

An attentive profile examination is required for the validation of Capillarys CDT results of cirrhotic patients. Reliability is significantly improved when samples with an improper separation are excluded. To date, no commercial test can confirm the excluded samples.

Improved capillary electrophoresis determination of carbohydrate-deficient transferrin including on-line immunosubtraction

The instrumental analysis of carbohydrate-deficient transferrin (CDT), a recognized marker of chronic alcohol abuse, is most commonly carried out by high-performance liquid chromatography (HPLC) or capillary zone electrophoresis (CZE). Between these two techniques, CZE shows higher efficiency and productivity, but is often reported to be inferior to HPLC in terms of selectivity, because of a less specific ultraviolet detection wavelength than HPLC. On these grounds, the present work was aimed at the development of an improved CZE method for CDT determination, including an on-line immunosubtraction step specifically aimed at enhancing the analytical specificity of CZE determination. The analytical conditions were as follows: uncoated fused silica capillary, 30 microm x 60 cm (L = 50 cm to detector); running buffer, 100 mmol/L borate and 6 mmol/L DAB (1,4-diaminobutane), pH 8.3; voltage, 30 kV; temperature, 25 degrees C; detection, 200 nm. Under the described CZE conditions, a baseline separation between all the CDT related peaks was achieved with good analytical performances in terms of both precision and accuracy. In order to achieve unequivocal recognition of the CDT peaks, an in-capillary immunosubtraction step was included by loading a plug of anti-human transferrin antibody solution after the sample plug. This analytical approach was applied successfully to recognize CDT peaks in the presence of potential interferences.

Alcoholic hepatitis 2010: A clinician’s guide to diagnosis and therapy

Alcoholic hepatitis (AH) remains a common and life threatening cause of liver failure, especially when it is severe. Although the adjective “acute” is frequently used to describe this form of liver injury, it is usually subacute and has been developing for weeks to months before it becomes clinically apparent. Patients with this form of alcoholic liver disease usually have a history of drinking heavily for many years. While certain aspects of therapy, mainly nutritional support and abstinence are well established, significant debate has surrounded the pharmacologic treatment of AH, and many institutions practice widely varying treatment protocols. In recent years a significant amount of literature has helped focus on the details of treatment, and more data have accumulated regarding risks and benefits of pharmacologic treatment. In particular, the efficacy of pentoxifylline has become increasingly apparent, and when compared with the risks associated with prednisolone, has brought this drug to the forefront of therapy for severe AH. This review will focus on the clinical and laboratory diagnosis and pharmacologic therapies that should be applied during hospitalization and continued into outpatient management. We conclude that the routine use of glucocorticoids for severe AH poses significant risk with equivocal benefit, and that pentoxifylline is a better, safer and cheaper alternative. While the full details of nutritional support lie beyond the scope of this article, nutrition is a cornerstone of therapy and must be addressed in every patient diagnosed with AH. Finally, while traditional psychosocial techniques play a major role in post-hospitalization care of alcoholics, we hope to make the medical clinician realize his or her role in reducing recidivism rates with early and frequent outpatient visits and with the use of baclofen to reduce alcohol craving.

Carbohydrate-Deficient Transferrin - A Contemporary Biomarker in Comparison with Traditional Laboratory Markers of Chronic Alcohol Abuse

Timely identification of excessive alcohol use and its potential complications is a prerequisite for successful treatment. Several routine tests have been used in laboratories that may help in diagnosing alcoholism, such as determination of MCV, AST, ALT, GGT, but it has been shown that they lack specificity and sensitivity. Contemporary bio-markers are increasingly being used today that may due to their unique characteristics help in discovering the onset of chronic alcohol abuse, as well as in abstinence and relapse monitoring. The term carbohydrate-deficient transferrin (CDT) stands for a small group of human transferrin isoforms (asialo, monosialo, and disialotran sferrin) with a lower degree of glycosylation in comparison to the dominant transferrin isoform (tetrasialotransferrin). Persons consuming large quantities of alcohol (≥50-80 g daily) over a period of at least two weeks have increased concentrations of transferrin isoforms lacking one (disialotransferrin) or both (asialotransferrin) carbohydrate chains. In this paper the traditional markers of chronic alcohol abuse (GGT, AST, ALT, and MCV) were determined, as well as the new biomarker CDT, after which diagnostic evaluation was performed and their usability and clinical value in routine laboratory practice were estimated. These markers were also determined in heavy alcoholics on admission into hospital and after two weeks of therapy, with the aim of estimating their diagnostic value for abstinence and relapse monitoring.