Carbohydrate-deficient transferrin in serum in patients with liver diseases

Sugar-coated bullets: Unveiling the enigmatic mystery 'sweet arsenal' in osteoarthritis

Glycosylation is a crucial post-translational modification process where sugar molecules (glycans) are covalently linked to proteins, lipids, or other biomolecules. In this highly regulated and complex process, a series of enzymes are involved in adding, modifying, or removing sugar residues. This process plays a pivotal role in various biological functions, influencing the structure, stability, and functionality of the modified molecules. Glycosylation is essential in numerous biological processes, including cell adhesion, signal transduction, immune response, and biomolecular recognition. Dysregulation of glycosylation is associated with various diseases. Glycation, a post-translational modification characterized by the non-enzymatic attachment of sugar molecules to proteins, has also emerged as a crucial factor in various diseases. This review comprehensively explores the multifaceted role of glycation in disease pathogenesis, with a specific focus on its implications in osteoarthritis (OA). Glycosylation and glycation alterations wield a profound influence on OA pathogenesis, intertwining with disease onset and progression. Diverse studies underscore the multifaceted role of aberrant glycosylation in OA, particularly emphasizing its intricate relationship with joint tissue degradation and inflammatory cascades. Distinct glycosylation patterns, including N-glycans and O-glycans, showcase correlations with inflammatory cytokines, matrix metalloproteinases, and cellular senescence pathways, amplifying the degenerative processes within cartilage. Furthermore, the impact of advanced glycation end-products (AGEs) formation in OA pathophysiology unveils critical insights into glycosylation-driven chondrocyte behavior and extracellular matrix remodeling. These findings illuminate potential therapeutic targets and diagnostic markers, signaling a promising avenue for targeted interventions in OA management. In this comprehensive review, we aim to thoroughly examine the significant impact of glycosylation or AGEs in OA and explore its varied effects on other related conditions, such as liver-related diseases, immune system disorders, and cancers, among others. By emphasizing glycosylation's role beyond OA and its implications in other diseases, we uncover insights that extend beyond the immediate focus on OA, potentially revealing novel perspectives for diagnosing and treating OA.

Vitamin B₁₂ and its binding proteins in hepatocellular carcinoma and chronic liver diseases

BACKGROUND

The vitamin B12 (B12)-binding protein haptocorrin (HC) has proven to be a potentially useful biomarker in patients with fibrolamellar hepatocellular carcinoma (HCC). Little is known concerning the level of HC and other B12-related proteins in patients with HCC as compared to patients with other chronic liver diseases (CLDs) and healthy controls. We hypothesized that HC could be a biomarker of HCC.

AIMS

To investigate levels of HC and B12-related proteins in HCC compared to CLDs and healthy controls.

METHODS

We investigated two patient populations: A cross-sectional cohort of HCC patients (n = 130), CLD patients (n = 102) and healthy controls (n = 46) and a cohort of 38 HCC patients studied at baseline and 1, 4, and 12 weeks following ablative treatment. Patients were evaluated by standard biochemistry, Child-Pugh-score and Barcelona Clinic Liver Cancer (BCLC) classification. We analyzed total B12 by routine methods and HC, transcobalamin (TC), B12 saturated TC (holoTC), and the soluble cell surface receptor for holoTC (sCD320) by in-house enzyme-linked immunosorbent assay.

RESULTS

HC showed higher median (range) levels for both HCC (590 [290-5860]) and CLD patients (620 [310-4010]) compared to controls (460 [250-2020]) (p < 0.01). Total B12, TC, holoTC, and sCD320 showed elevated levels in both HCC and CLD compared to controls. Only holoTC changed following treatment, without a concurrent change in TC.

CONCLUSION

B12 and B12-related proteins (total B12, HC, TC, holoTC, and sCD320) show elevations in both HCC and CLD patients compared to controls, suggesting a relation to CLD in general rather than to primary liver cancer. Thus, HC is not useful as a biomarker for HCC.

Combined effects of alcohol and hepatitis C: a secondary analysis of alcohol use biomarkers and high-risk behaviors from two medication trials for alcohol dependence

OBJECTIVES

The goal of this secondary analysis was to examine the combined effects of HCV infection and recent alcohol use on baseline biologic markers of alcohol consumption in two outpatient medication trials for alcohol dependence. In addition, the relationship between Hepatitis C virus (HCV) infection and behavioral risk factors for HCV infection in these clinical populations were examined.

METHODS

Data (n=345) from two randomized, placebo-controlled trials of naltrexone and psychosocial treatment for alcohol dependence (Study I, n=212) and comorbid alcohol and cocaine dependence (Study II, n=133) were used to examine baseline measures of HCV risk behaviors (injection drug use, needle sharing), and biomarkers of alcohol use (AST, ALT, GGT and CDT) were compared by HCV serostatus first within each study and then across studies.

RESULTS

Although groups had differing sociodemographic profiles (as indicated by race, marital status, level of education) subjects in Study I exhibited no statistically significant differences from the Study II cohort in HCV prevalence (12.7 vs. 20.0%, p=0.07), lifetime history of injection drug use (13.8 vs. 22.0%, p=0.74), lifetime history of needle sharing (9.1 vs. 18.0%, p=0.62). As such, the data from both studies were analyzed together. Regardless of drinking status, HCV infection was significantly associated with an upward shift in the baseline level of ALT, AST, and GGT (p<0.006 for all measures) and a downward shift in baseline CDT (p=0.002). When using standard laboratory cutoff values to determine clinically significant elevations, HCV seropositivity was significantly associated with elevations in ALT, AST, GGT (p<0.001), and with decreases in CDT (p=.002).

CONCLUSIONS

These data emphasize the importance of evaluating HCV infection and HCV risk behaviors at intake in medication trials for alcohol dependence and also raise questions regarding the use of cutoff scores for ALT, AST, GGT and CDT levels as biologic markers of alcohol use in subjects when HCV status is unknown.

The carbohydrate-deficient transferrin test in hospital practice

We report an experience in two hospital populations of the use of a commercially available kit for the detection of carbohydrate-deficient transferrin (CDT). Patients from a drug and alcohol unit and a gastroenterology clinic at two hospitals were selected for the study. Sera were used from blood samples collected for routine biochemical assays. All patients had a specific alcohol history taken by one clinician and CDT results were correlated with reported alcohol intake by the patient and where relevant by their relatives. Sensitivity and specificity of the CDT assay were calculated using an alcohol intake of 60 g/day as the cut-off point for detection of heavy drinking. The CDT assay had a specificity of 95%; a sensitivity of 80% and a 90% positive and 89% negative predictive value. The severity and type of liver disease had little influence on the CDT result and a high alcohol intake was the only predictor of a raised CDT concentration. The assay provided information not available from routine investigations in some patients and also proved useful in monitoring patients over periods of up to 4 years. The test has a role in the evaluation of patients in a hospital practice where routine histories of alcohol intake may lack sensitivity and where other diseases may cause routine liver tests to be unreliable.

Primary biliary cirrhosis is not a clinical condition for increased carbohydrate-deficient transferrin: experience with four independent CDT analysis methods

BACKGROUND

Primary biliary cirrhosis (PBC) is considered as an important cause for increased carbohydrate-deficient transferrin (CDT). The underlying pathomechanism is difficult to explain by the pathogenesis and/or consequences of PBC. We tested whether PBC causes increased CDT results with current CDT analysis methods and, if so, whether this depends on the CDT analysis principle.

METHODS

48 serum samples from PBC patients were analyzed by HPLC, microcolumn CDT and non-CDT fractionation followed by a turbidimetric immunoassay, particle-enhanced immunonephelometry with monoclonal CDT antibodies, and capillary electrophoresis. The test-specific decision limits were used for categorization of the CDT analysis results into normal and increased values.

RESULTS

HPLC: 47 normal/1 increased, microcolumn+TIA: 46 normal/2 increased, particle-enhanced immunonephelometry: 41 normal/7 increased, capillary electrophoresis: 48 normal CDT results. After combining an immunological CDT test (microcolumn+TIA or particle-enhanced immunonephelometry) as the screening method with a physico-chemical CDT test (HPLC or electrophoresis) as the confirmatory method, 1 case remained with increased CDT values by the screening (value 2.6%, cut-off 2.5%, particle-enhanced immunonephelometry) and confirmatory (value 1.8%, cut-off 1.75%, HPLC) analysis.

CONCLUSIONS

PBC should no longer be overstressed as an important cause for false-positive CDT results regarding chronic alcohol abuse. In the presence of odd CDT results, PBC should be considered in the anamnestic exploration. However, PBC is not by itself a cause for increased CDT values.

Alcohol Biomarker Screening in Medical and Surgical Settings

This article highlights the proceedings of a symposium presented at the 28th Annual Meeting of the Research Society on Alcoholism in Santa Barbara, CA, on June 28, 2005, organized and chaired by Peter Miller. The presentations included (1) Screening for Alcohol Use Disorders in Surgical and Trauma Patients, presented by Claudia Spies; (2) Are Serum Levels of %CDT and GGT Related to Severity of Liver Biopsy Inflammation, Fibrosis, and Steatohepatitis in Patients with Hepatitis C? by Martin Javors; (3) Biochemical Alcohol Screening in the Treatment of Hypertension, presented by Peter Miller; and (4) The Cost-Effectiveness of a New Biomarker, CDT, in a Primary Care Sample, by Michael Fleming. Presentations were discussed by Raymond Anton.

Validity of carbohydrate-deficient transferrin (%CDT), gamma-glutamyltransferase (gamma-GT) and mean corpuscular erythrocyte volume (MCV) as biomarkers for chronic alcohol abuse: a study in patients with alcohol dependence and liver disorders of non-alcoholic and alcoholic origin

AIM

To test the clinical performance of carbohydrate-deficient transferrin (%CDT), gamma-glutamyltransferase (gamma-GT) and mean corpuscular erythrocyte volume (MCV) as biomarkers for alcoholism with a special focus on patients suffering from liver diseases.

DESIGN

Well-characterized collectives of alcohol-dependent patients with current consumption (ALC patients, n = 101), and relevant control groups (115 social drinkers, 46 patients with unspecifically increased gamma-GT, 51 hepatitis patients and 20/31 patients with non-alcohol/alcohol-dependent liver cirrhosis) were included into the study. The Positive Alcohol Use Disorders Test (AUDIT) score, International Classification of Diseases version 10 (ICD-10)/Diagnostic and Statistical Manual version IV (DSM-IV) criteria and blood drawn within 4 days of last drinking were inclusion criteria for subjects with regular heavy drinking. %CDT was determined using an automated assay which recently had been completely modified.

FINDINGS

Median AUDIT scores of patients without/with regular heavy drinking were 1-3/27. The following medians/95th percentiles were obtained for %CDT: social drinkers 2.2/3.0, patients with unspecifically increased gamma-GT 2.1/3.0, hepatitis 2.0/4.4, non-alcohol-dependent liver cirrhosis 2.4/4.8, alcohol-dependent liver cirrhosis 3.0/5.9, ALC patients 3.9/14.9. Differences between patients without and with alcohol abuse were highly significant (P < 0.001). No differences in CDT values were found between males and females. There was no correlation between %CDT values, gamma-GT, MCV and the amount of alcohol consumed in ALC patients; 3.0%CDT (95th percentile social drinkers) is proposed as cut-off for the test used (Tina-quant %CDT 2nd-generation). At this cut-off, the sensitivity for ALC patients was 73.3%, whereas gamma-GT/MCV had a sensitivity of 71.3%/64.4%. Multivariate analysis performed at 95% specificity resulted in an improvement of the sensitivity by combining %CDT with gamma-GT (83.2%). A further enhancement of the sensitivity to 88.1% was obtained by combination of %CDT, gamma-GT and MCV. The diagnostic specificity of %CDT calculated at the cut-off of 3% was 93.5% in patients with unspecifically increased gamma-GT, 88.2% in hepatitis patients and 70.0% in patients with non-alcohol-dependent liver cirrhosis. %CDT was more specific in these patient collectives than MCV, and especially more than gamma-GT (specificity in hepatitis 52.9%, and 35.0% in non-alcohol-dependent liver cirrhosis).

CONCLUSION

%CDT is of high diagnostic value to support diagnosis of alcohol-use disorders. The specificity of this marker in patient groups with liver disorders is superior to the biomarkers gamma-GT and MCV.

Pretransplant screening of sobriety with carbohydrate-deficient transferrin in patients suffering from alcoholic cirrhosis

Sufficient assessment of potential candidates for orthotopic liver transplantation (OLT) is the most important factor for a low alcohol relapse rate after transplantation in patients suffering from alcoholic cirrhosis. In the current study the efficiency of pretransplant screening with carbohydrate-deficient transferrin (CDT) was analysed in patients on the waiting list for OLT. A prospective study was performed in 44 patients who had undergone OLT for alcoholic cirrhosis. All patients had had pretransplant assessment by a specialist psychologist and were found to have no problems with alcohol. Pre- and post-transplant CDT monitoring was performed. Overall, 790 CDT values were measured in the study population. The median observation period was 2.1 months before and 41.2 months after transplantation, respectively. In 35 patients (80%) pretransplant CDT values were found to be above the reference value, but only one patient suffered an alcohol relapse after transplantation. Of the nine patients (20%) who demonstrated normal CDT before transplantation, two suffered an alcohol relapse after transplantation. CDT is a very useful marker for the monitoring of an alcohol relapse in patients following OLT for alcoholic cirrhosis, as has been previously indicated. However, CDT does not appear to be useful as a pretransplant screening marker for selection of potential transplant candidates suffering from alcoholic cirrhosis.

Carbohydrate-deficient transferrin (CDT)--a biomarker for long-term alcohol consumption

Carbohydrate-deficient transferrin (CDT) is a biomarker for chronic alcohol intake of more than 60 g ethanol/d. It has been reported to be superior to conventional markers like gamma-glutamyltransferase (GGT) and mean corpuscular volume MCV). This review covers theoretical and analytical aspects, with data from controlled drinking experiments and from different population subgroups such as subjects with different liver diseases or different drinking patterns. CDT determinations are particularly indicated in (1) cases of chronic alcohol consumption and relapses after withdrawal, (2) license reapplication after driving under alcohol influence, (3) differentiating patients with enzyme-inducing medication from those with alcohol abuse, 4) congenital disorders of glycosylation such as carbohydrate-deficient glycoprotein syndrome Ia (CDGS Ia), and (5) patients treated for galactosemia. The main advantage of CDT is its high specificity, as evidenced in combination with increased alcohol consumption. CDT values are not markedly influenced by medication except in immunosuppressed patients, who may show low CDT values. In general, CDT values appear less elevated after alcohol intake in women. The main disadvantage is the relatively low sensitivity. Hence, this parameter is not suitable for screening for subjects with alcohol abuse in the general population. As CDT, GGT, and MCV are connected with chronic alcohol consumption by different pathophysiological mechanisms, a combination of these parameters will further improve the diagnostic value.

Value of determining carbohydrate-deficient transferrin isoforms in the diagnosis of alcoholic liver disease

OBJECTIVE

To determine whether isoform separation of carbohydrate-deficient transferrin (CDT) is of value in the diagnosis of alcoholic liver disease (ALD) and is specific to ALD when compared with other liver diseases.

PATIENTS AND METHODS

During 1995 and 1996, 47 patients with ALD were evaluated with CDT at the Mayo Clinic in Rochester, Minn. The diagnosis of ALD was based on biochemical and histological analyses and on a history of drinking that exceeded 5 years with an average alcohol intake of more than 60 g/d. Disease controls included nonalcoholic steatohepatitis (NASH) (n = 26) and other liver disease (n = 22). Normal controls (n = 21) were healthy individuals without liver disease. Transferrin isoforms were quantified by densitometry of Coomassie-stained transferrins after affinity purification and isoelectric focusing. The pentasialo, tetrasialo, trisialo, disialo, monosialo, and asialo isoforms were quantified as percentages of total band densities.

RESULTS

Receiver operating characteristic (ROC) curves were constructed for each isoform. The curves for total desialated isoforms (sum of disialo, monosialo, and asialo) displayed the best relationship between sensitivity and specificity with an ROC-area under the curve (AUC) of 0.922. The ROC-AUC values for individual transferrin isoforms in ALD vs NASH for pentasialo, tetrasialo, trisialo, disialo, monosialo, and asialo were 0.806, 0.917, 0.885, 0.933, 0.804, and 0.785, respectively. Only 58% of patients with ALD were detected at a specificity that excluded ALD in 84% of those who did not have it.

CONCLUSION

Within alcohol ingestion times reported to us, no associations with recent drinking were observed. Alcohol as a cause of liver disease is not perfectly established by CDT analysis, although a high total CDT value favors ALD over NASH.

Inhibition of system A amino acid transport activity by ethanol in BeWo choriocarcinoma cells

OBJECTIVE

Our purpose was to investigate the influence of ethanol on system A amino acid transporter in BeWo cells.

STUDY DESIGN

BeWo cells were cultured in the absence or presence of ethanol. The function of system A was monitored by the transport of alpha-(methylamino)isobutyric acid. Messenger RNA levels for system A were assessed by Northern analysis.

RESULTS

Treatment of BeWo cells with ethanol reduced the activity of system A. The effect was dose and treatment time dependent. The decrease in system A activity was 38% +/- 3% at 0.75% ethanol with a 16-hour treatment time. The activities of several other transporters tested were not affected. The effect on system A activity was associated with a decrease in the maximal velocity of the transport system without affecting the substrate affinity. Ethanol did not alter the messenger RNA levels for system A.

CONCLUSION

Exposure of BeWo cells to ethanol significantly reduces the function of system A. This finding has potential implications that may be relevant to the pathogenesis of the fetal alcohol syndrome.

Carbohydrate deficient transferrin in abstaining patients with end-stage liver disease

BACKGROUND

Carbohydrate deficient transferrin (CDT), a biochemical marker of chronic alcohol consumption, is used by researchers and clinicians alike in a variety of populations. Levels of CDT may be affected by certain types of medical illnesses and conditions. Thus the interpretation of CDT results may need to be carefully examined in these populations. Because CDT is synthesized, glycosylated, and secreted by the liver, the use of CDT values in patients with liver disease has been an area of focused interest.

METHODS

We evaluated the CDT values of 79 abstaining patients with end-stage liver disease. These patients were recruited from a liver transplant clinic while they were listed and waiting for transplantation. Patients were determined to be abstaining both by interview and by random blood alcohol levels in those with a diagnosis of alcoholic liver disease. The severity of the liver disease was categorized by the Child-Pugh score. Correlations were determined between CDT values and liver enzymes, and Child-Pugh scores and liver diagnosis.

RESULTS

Nearly 50% of the patients had a CDT value of 2.6% or above, indicating a clinically positive value. There were strong correlations between CDT and a number of biochemical and physical variables, most importantly the Child-Pugh score (r = 0.52, p = 0.000). Specific liver diseases were not associated with absolute CDT values. However, patients with hepatitis C (HCV) had a significantly higher chance of having a clinically positive CDT compared with patients with other types of liver diseases.

CONCLUSIONS

These results suggest that an elevated CDT value may not accurately represent alcohol consumption in patients with advanced liver disease. In fact, in such patients, the CDT may become a marker for the degree of liver impairment in alcoholic and nonalcoholic liver disease. CDT values should be viewed with caution in any patient with liver disease especially when the degree of cirrhosis reaches a Child-Pugh score of C (total score of 10 or above).

Carbohydrate-deficient transferrin and sialidase levels in coronary heart disease

Transferrin is a N-glycosylated glycoprotein and plays an important role in iron transport from sites of absorption and storage to sites of utilization. The main component of normal serum transferrin contains two biantennary glycans, each consisting of 2 mol of sialic acid (Tetrasialo transferrin). Normal serum also contains small amounts of tri- and disialotransferrin. We have undertaken this study to investigate the levels of serum carbohydrate-deficient transferrin (Desialotransferrin) and sialidase levels in patients with coronary heart disease. In patient group, serum desialotransferrin and sialidase levels were found to be significantly higher than control group (p < 0.01 and p < 0.001, respectively). We conclude that increased activity of sialidase may be responsible for increased desialotransferrin in patients with coronary heart disease. Serum desialotransferrin levels may be useful critaria to diagnosis and pathogenesis of coronary heart disease.

Vitreous humor carbohydrate-deficient transferrin concentrations in the postmortem diagnosis of alcoholism

Deaths from the effects of alcohol intoxication are encountered routinely in forensic practice. In an important number of cases difficulty may arise in interpreting the significance of results obtained in the autopsy. In clinical practice biochemical markers, particularly serum gamma-glutamyl-transpeptidase (GGT), alanine aminotransferase (ALT), aspartate transaminase (AST), carbohydrate-deficient transferrin (CDT), and erythrocyte mean corpuscular volume are used to diagnose heavy alcohol consumption. CDT is used as a reliable and specific marker. In postmortem diagnosis, because of the difficulty in interpreting blood alcohol levels and relatively non-specific pathological features, biochemical compounds have been studied for use as possible markers. The aim of this study was to evaluate the usefulness of the postmortem determination of CDT in vitreous humor as a confirmation of antemortem alcoholism. CDT levels were studied in 66 male cadavers with a mean age of 55.9 years (S.D. 17.0, range 22-87 years) with a mean postmortem interval of 17.9 h (S.D. 11.4, range 4-72 h). Cases were assigned to two diagnostic groups according to the antemortem diagnosis of alcoholism. Statistically significant differences were found for CDT and ALT concentrations between the two diagnostic groups. The highest vitreous humor levels of CDT and ALT were obtained in the group of cases with a previous diagnosis of alcoholism. Our results suggest that vitreous humor CDT levels are useful in cases where the postmortem diagnosis of alcoholism is hindered by the non-specificity of data.

Carbohydrate deficient transferrin for detection of alcohol relapse after orthotopic liver transplantation for alcoholic cirrhosis

Early diagnosis and monitoring of an alcohol relapse in patients after orthotopic liver transplantation for alcoholic cirrhosis is of importance for the long-term outcome. A prospective study of 97 patients who underwent orthotopic liver transplant for alcoholic cirrhosis has been performed. All of the recipients considered for analysis survived for at least 3 months and were under the care of one specialist psychologist. Mean follow-up amounted to 48.5+/-1.4 months. The rates of alcohol relapse at 1 and 3 years after orthotopic liver transplant were 6 and 9%, respectively. Carbohydrate-deficient transferrin is a biological marker for alcohol abuse independently of liver disease and has been used for the first time ever in liver graft recipients. A total of 830 values were included prospectively in the study population. Detection of alcohol relapse had a sensitivity of 92% and a specificity of 98%. Changes in carbohydrate-deficient transferrin levels indicated clandestine and sporadic drinking after transplantation. Furthermore, clinical events were not found to influence carbohydrate-deficient transferrin, either in patients with or without alcoholic relapse. In our opinion, carbohydrate-deficient transferrin is a useful screening marker for alcohol relapse in patients after orthotopic liver transplant for alcoholic cirrhosis, to select those patients who need special attention from the psychologist.

Carbohydrate-deficient transferrin is not a useful marker for the detection of chronic alcohol abuse

BACKGROUND

The role of carbohydrate-deficient transferrin (CDT) as a reliable marker for the detection of chronic alcohol abuse has been discussed controversially.

METHODS

Therefore, we investigated CDT in the sera from 405 subjects with different alcohol intake. Besides healthy control subjects (n = 42), inpatients and outpatients in a department of gastroenterology (n = 325) and patients admitted to a department of otorhinolaryngology (n = 38) were studied. A total of 213 patients suffered from various forms of liver diseases, and 89 patients had liver transplantation. CDT values were determined by a double-antibody radioimmunoassay.

RESULTS

In the 241 alcohol-abstinent subjects, CDT levels ranged from 3 to 90 units L-1 (median = 12); the 92 moderate drinkers (20-60 g of alcohol per day) showed values from 3 to 40 units L-1 (median = 12), and the 72 subjects with chronic alcohol abuse (> 60 g per day) revealed CDT levels from 3 to 100 units L-1 (median = 16). The diagnostic specificity for alcohol abuse was 86.8% for men (sensitivity 36.9%) and 95% for women (sensitivity 0%).

CONCLUSION

Our data indicate that measurement of CDT does not reach clinical use in the detection of chronic alcohol abuse in an unselected population because of its insufficient specificity and sensitivity.

Carbohydrate deficient transferrin in alcoholic and non-alcoholic liver disease: a comparison of two assay methods

Carbohydrate-deficient transferrin (CDT) was assayed in 105 patients with non-alcohol-related liver diseases, 50 patients with alcohol-induced liver disease and 40 alcohol misusers with minimal hepatic dysfunction. The patients with liver disease were hospitalized for assessment of suitability for orthotopic liver transplantation. CDT was measured by two commercially available micro anion exchange methods; CDTect (Pharmacia) and %CDT (AXIS). Additionally, total transferrin was measured to allow expression of the CDTect results as 'relative' measurements. Overall, 41/105 (39%) of patients with non-alcohol-related liver diseases had a raised CDTect result, 13/105 (12%) had a raised %CDT result and 26/105 (25%) an abnormal CDTect/total transferrin ratio. In general, patients with cholestatic liver disease, primary biliary cirrhosis or primary sclerosing cholangitis had more 'false positive' results by CDTect than did those with viral or autoimmune hepatitis. The sensitivity of the two methods for the detection of alcohol misuse was similar; CDTect 77%, %CDT 65% and CDTect/total transferrin ratio 70%. This was, however, lower than the sensitivity of the conventional marker GGT (82%). In patients with severe liver disease, where up to 30% of the serum total transferrin concentrations fall outside the reference range, 'relative' CDT methods have greater specificity than 'absolute' measurements.

A simple method for carbohydrate-deficient transferrin measurements in patients with alcohol abuse and hepato-gastrointestinal diseases

Carbohydrate-deficient transferrin (CDT) is known to be increased in alcohol abuse. Several methods were developed for its measurement (e.g. isoelectric focusing with Western blotting or immunofixation, anion-exchange chromatography followed by immunoassays). We describe a greatly simplified isoelectric focusing technique which does not require immunofixation. CDT results obtained with this method were compared to other biological markers of alcohol abuse, i.e. mean corpuscular volume (MCV), aspartate aminotransferase (ASAT) and gamma-glutamyl-transferase (GGT), in 55 patients distributed in three groups (i.e. healthy control subjects, control patients suffering from various hepato-gastrointestinal diseases and alcohol abusing patients). Sensitivity and specificity were 33-89%, 61-57%, 89-49% and 83-100% for MCV, ASAT, GGT and CDT, respectively. We conclude that our method is highly suitable for routine clinical use.

Carbohydrate-deficient transferrin as a marker of alcohol consumption in male patients with liver disease

Carbohydrate-deficient transferrin (CDT) has been proposed as a marker of alcohol abuse. However, its value in patients with associated liver disease is still controversial. The aim of the study was to investigate the usefulness of CDT as a marker of alcohol consumption in patients with liver disease. We measured serum levels of CDT and those of commonly used hematological and biochemical markers, mean corpuscular volume (MCV), transaminases (AST and ALT), and gamma-glutamyltransferase in 179 male subjects divided into four groups: 45 active drinkers (13 with normal liver, 21 with fibrosteatosis, and 11 with liver cirrhosis), 45 abstinent chronic alcoholics (18 with and 27 without liver disease), 58 patients with nonalcoholic liver disease, and 31 healthy controls. Serum CDT in active alcoholics was 37.5 +/- 3.6 units/liter, being significantly higher than that of abstinent alcoholics (20.3 +/- 1.5 units/liter), patients with nonalcoholic liver disease (18.1 +/- 1.1 units/liter), and controls (13.1 +/- 0.8 units/liter). Contrary to the other markers, no significant differences were observed in CDT values in relation with the presence and severity of liver disease in either the active drinkers or in the abstinent alcoholics. The sensitivity and specificity of CDT as a marker of alcoholism in the series as a whole was 64% and 82%, respectively, similar to the best conventional marker, MCV (64 and 82%). In patients with liver disease, CDT maintained good sensitivity (72%) and specificity (83%). Receiver operating characteristic analysis confirmed that CDT had a similar diagnostic value to that of MCV, but better than gamma-glutamyl-transferase and transaminases for the detection of alcohol abusers. The good diagnostic efficacy of CDT remained unchanged when analyzing only patients with liver disease. We conclude that serum CDT is a good marker of alcoholism and is less influenced than the currently used biochemical markers for associated liver disease. Thus, CDT is an effective laboratory test to detect alcohol abuse regardless of the presence of alcoholic liver disease.

Serum carbohydrate-deficient transferrin in patients with nonalcoholic liver disease and with hepatocellular carcinoma

Serum carbohydrate-deficient transferrin (CDT) is used as a reliable and specific marker of alcohol consumption. However, recent studies have shown false-positive CDT test results in nonalcoholic liver disease. We examined the clinical significance of serum CDT in nonalcoholic liver disease, especially hepatocellular carcinoma. Serum CDT was measured in 23 teetotallers, 56 patients with alcoholic liver disease, 84 patients with viral liver disease and 67 patients with hepatocellular carcinoma, with an Axis %CDT radioimmunoassay kit, and the results were expressed as percentages of the total transferrin (%CDT). The mean serum %CDT value was increased 1.8-fold in alcoholic liver fibrosis and 3.8-fold in alcoholic liver cirrhosis compared with the teetotallers. The serum %CDT values in viral chronic hepatitis were similar to those of the teetotallers, and were increased 2.0-fold in viral liver cirrhosis. False-positive results were found in 10 (37%) of the 27 patients with viral liver cirrhosis. The mean serum %CDT value was increased 2.5-fold in hepatocellular carcinoma, and false-positive results were found in 31 (46%) of the 67 patients. The serum %CDT value was related to the severity of Child grade, the size of tumor and the grade of histological differentiation. These results suggest that the ability of serum CDT test to detect chronic alcoholism may be reduced in patients with nonalcoholic liver cirrhosis and those with hepatocellular carcinoma.

Carbohydrate deficient transferrin (CDT) in alcoholic cirrhosis: a kinetic study

BACKGROUND/AIMS

Carbohydrate deficient transferrin has been introduced as a marker of excessive alcohol intake. The present study was undertaken in order to measure the circulating level of carbohydrate deficient transferrin in patients with alcoholic cirrhosis and to assess arteriovenous kinetics of carbohydrate deficient transferrin in liver and kidney.

METHODS/RESULTS

The median value of serum carbohydrate deficient transferrin was 16.0 U/l in patients with alcoholic cirrhosis (n = 41), and this value was not significantly different from that of a normal control group (median 17.4 U/l, n = 55, ns). Carbohydrate deficient transferrin was significantly higher in patients with cirrhosis and high current alcohol intake than in abstaining patients (20 vs. 14 U/l, p < 0.05). Similarly, controls with a high current alcohol intake (> 50 g/day) had a significantly higher carbohydrate deficient transferrin concentration than controls with a low alcohol intake (< 10 g/day) (36 vs. 14.9 U/l, p < 0.005). No significant differences were detected between carbohydrate deficient transferrin in artery and liver vein or artery and renal vein, either in patients with alcoholic cirrhosis (n = 11) or in controls (n = 8), which indicates a slow turnover rate of carbohydrate deficient transferrin. Food ingestion did not affect the circulating level of carbohydrate deficient transferrin, and the analysis of carbohydrate deficient transferrin was almost unaffected by the presence of ethanol in plasma within the biological range (ethanol 0-100 mmol/l).

CONCLUSIONS

Our results suggest that measurement of carbohydrate deficient transferrin may be used in patients with alcoholic cirrhosis. High current alcohol intake is associated with higher carbohydrate deficient transferrin levels than in those with low alcohol intake, but the overlap is substantial in patients with cirrhosis. Carbohydrate deficient transferrin has a low turnover rate in both patients with cirrhosis and normals.

Isoelectric focusing (IEF) and immunofixation for determination of disialotransferrin

OBJECTIVES

A new simplified method for detection and quantitation of disialontransferrin in serum is described.

DESIGN AND METHODS

The method is based on polyacrylamide gel isoelectric focusing, direct immunofixation with a specific antibody, and measurement by computerized scanning densitometry. Disialotransferrin levels were determined in 24 teetotallers and 34 alcoholics at 3 moments during detoxification. Three groups of drinkers were arranged: group 1 (without), group 2 (with light), and group 3 (with severe hepatitis).

RESULTS

The metho showed very good reproducibility and accuracy with a coefficient of variation between 5 to 8%. Alcoholic patients could be clearly separated from teetotallers, with a specificity of 100% and a sensitivity of 94%. After 12 days of alcohol withdrawal, disialotransferrin values declined in alcoholics but remained slightly high. They were not influenced by the severity of liver disease. No significant difference was found between the 3 groups.

CONCLUSIONS

An easy-to-perform, sensitive, and inexpensive method has been developed to quantify disialotransferrin that can be used by laboratories almost everywhere.

Sensitivity and specificity of carbohydrate-deficient transferrin as a marker of alcohol abuse are significantly influenced by alterations in serum transferrin: comparison of two methods

Despite a number of investigations suggesting the value of carbohydrate-deficient transferrin (CDT) as a marker of alcohol abuse, a variety of issues on the applicability of CDT measurements in clinical settings have remained unexplored. Earlier studies in this field have focused on the relationship of CDT and the amount of alcohol consumption or presence of liver disease, whereas the influence of alterations in serum transferrin concentrations on CDT has received less attention. In this study, we compared two different methods for measuring CDT (CDTect and %CDT) and total transferrin concentrations in a sample of 83 alcohol abusers (20 patients with alcoholic liver disease and 63 heavy drinkers who were devoid of liver disease, despite excessive alcohol consumption) and 89 controls, who were social drinkers or abstainers. The control population included 53 hospitalized patients with expected abnormalities in serum transferrin concentrations caused by conditions such as negative iron balance, pregnancy, or nonalcoholic liver disease. Both methods gave significantly higher values in alcohol abusers than in controls (p < 0.01), but the overall sensitivity for detecting alcohol abuse was clearly higher for CDTect (59%) than for %CDT (34%). The correlation between the results obtained by the two methods (r = 0.629) significantly improved, when the CDTect values were replaced by the ratio of CDTect/total transferrin (r = 0.770) (p < 0.05). There was a positive correlation between the CDTect and serum transferrin (r = 0.201, p < 0.01), which was significant both in the alcoholics (r = 0.240, p < 0.05), and especially in the controls (r = 0.727, p < 0.001). A significant inverse correlation emerged between %CDT and total transferrin (r = -0.302, p < 0.01). The sensitivities of CDTect and %CDT for correctly classifying alcohol abusers in the subgroup of alcoholic liver disease patients were 90% and 70% and in the subgroup of heavy drinkers without liver disease (49% and 22%), respectively. Specificities for CDTect and %CDT in this sample were 81% and 100%, respectively. However, in the subgroup of hospitalized control patients with abnormal serum transferrin, the specificity of CDTect was only 48%. According to present data, CDTect seems to be more sensitive than %CDT for detecting alcohol abuse. However, any alteration in serum total transferrin concentration markedly decreases the assay specificity. This should be considered when interpreting the assay results in patients with elevated serum transferrin, such as iron deficiency, pregnancy, or liver diseases.

Carbohydrate-deficient transferrin in alcohol and nonalcohol abusers with liver disease

Carbohydrate-deficient transferrin (CDT) has been demonstrated to be a marker of prolonged heavy alcohol consumption. We compared this marker with gamma-glutamyltranspeptidase (GGT) and mean corpuscular volume (MCV) in alcohol and nonalcohol abusers with liver disease. Our results confirm that the sensitivity of CDT in alcoholics is high, although lower than that of GGT and MCV; however, the specificity of CDT was higher than that of the other two markers. This finding supports the notion that CDT is only partially influenced by the presence of liver damage, whereas increases of GGT and MCV are greatly affected by several factors, including liver damage and drugs. Moreover, we observed that the sensitivity and the specificity of CDT were greater than those of GGT and MCV in younger drinkers.

Elevated levels of serum carbohydrate deficient transferrin are not specific for alcohol abuse in patients with liver disease

BACKGROUND

Serum carbohydrate deficient transferrin is a marker of chronic alcohol consumption; it increases above normal in healthy individuals after a daily alcohol intake of more than 60 g/d for more than 2 weeks. The influence of liver disease itself on carbohydrate deficient transferrin levels has not been sufficiently established.

METHODS

We investigated serum levels of carbohydrate deficient transferrin in 196 consecutive patients admitted to our Gastroenterology and Hepatology Unit and correlated this parameter with the patients' statements about alcohol intake during the previous 2 weeks and with other markers of chronic alcohol consumption.

RESULTS

In our patient population, carbohydrate deficient transferrin had the best overall performance with respect to sensitivity (88%), specificity (82%), and negative predictive value (98%), as compared to other markers, although specificity was much lower than previously reported in patients without liver disease. In the group of patients with liver disease, sensitivity and specificity were 90% and 73%, respectively, and in patients without liver disease, 80% and 88%. The negative predictive value was excellent (96% for patients with liver disease and 99% for patients without liver disease).

CONCLUSIONS

Thus, in a patient with a negative interview for chronic alcohol abuse and normal carbohydrate deficient transferrin level, alcohol is unlikely to be the cause of liver disease, and further investigations to establish the etiology of liver disease are warranted. An increased carbohydrate deficient transferrin level, however, cannot be regarded as reliable evidence for chronic alcohol abuse in patients with liver disease.

Gamma-glutamyltranspeptidase and carbohydrate deficient transferrin: alternative measures of excessive alcohol consumption

Both gamma-glutamyltranspeptidase and carbohydrate-deficient transferrin have been extensively researched as biological markers of heavy alcohol consumption. The current study briefly describes each test, identifies subject variables that influence their relative sensitivities and specificities, and examines issues surrounding use of the two markers in combination. In addition, this study suggests five design features that should characterize projects evaluating the validity of biochemical markers.

Carbohydrate-deficient transferrin as a marker of alcohol abuse: relationship to alcohol consumption, severity of liver disease, and fibrogenesis

Carbohydrate-deficient transferrin (CDT) measurements have been widely examined as a marker of excessive alcohol consumption, yet the information on the sensitivity of this method has remained controversial. In addition, little is known of the relationship of this marker and the severity of alcoholic liver disease (ALD). To clarify these issues, we analyzed serum samples from 373 alcohol abusers, including 200 problem drinkers with no apparent liver pathology, 173 patients with clinical or morphological evidence of ALD, and 42 healthy controls. CDT was analyzed by anion-exchange chromatography followed by radioimmunoassay. At a specificity of 100%, the sensitivity of CDT was 36% in problem drinkers reporting a mean of 710 +/- 80 (mean +/- 2SE) g of ethanol/week, as compared with the sensitivities of 44% and 35% for gamma-glutamyltranspeptidase (GGT) and mean corpuscular volume (MCV), respectively. In a subgroup of problem drinkers (n = 51) with the highest ethanol intakes (1160 +/- 180 g of ethanol/week) and severe dependence, the sensitivity of CDT increased to 64%, compared with 55% for GGT and 39% for MCV. In ALD, the CDT values were significantly higher than in the alcoholics with nonliver pathology. However, when such patients were classified according to the clinical, laboratory, and morphological severity of liver disease, CDT was found to be primarily elevated in those with the early stage of ALD, such that there was a significant negative correlation between CDT and the combined morphological index of disease severity (rs = -0.315, p < 0.05). ALD markers of fibrogenesis were elevated more frequently than CDT, showing significant positive correlations with the indices of disease severity.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate-deficient transferrin--a valid marker of alcoholism in population studies? Results from the Copenhagen City Heart Study

Carbohydrate-deficient transferrin (CDT) was analyzed by a modified radioimmunoassay test in a random population sample of 400 individuals, and results were compared with reported alcohol intake derived from a structured questionnaire. Among the 180 men, the test was found to be acceptable with respect to detecting harmful alcohol intake (> 35 beverages/week) and alcohol intake above the recommended level (21 beverages/week), although the positive predictive values were low. Among the 220 women, the test was invalid with low predictive values. CDT was compared with other known markers of high alcohol intake, and it was observed that CDT had higher sensitivity and specificity than AST and short Michigan Alcoholism Screening Test (sMAST) in men, whereas the positive and negative predictive values were low in all tests. A combination of CDT and AST proved to be a better marker of both harmful alcohol intake and alcohol intake above the recommended level than the other markers. Neither CDT, AST, CDT/AST, nor sMAST proved to be useful as markers of alcohol intake in women. There were no differences between the values for pre- and postmenopausal women. These results from a population survey indicate that CDT is a marker of alcohol intake among men, although not ideal, but CDT cannot be used in the screening of harmful alcohol intake in women.

A comparison between two commercial methods for determining carbohydrate deficient transferrin (CDT)

The performance of CDTect (Kabi-Pharmacia, Uppsala, Sweden) and two versions of AXIS % CDT (AXIS Biochemicals, Oslo, Norway) for determining carbohydrate deficient transferrin (CDT) was examined in 502 consecutive patients admitted to the Department of Medicine, Aker University Hospital. The sensitivity for detecting an alcohol consumption > or = 50 g/day for the last 4 weeks was 69% for CDTect, 65% for AXIS % CDT, version 1 (AX CDT 1) and 50% for AXIS % CDT, version 2 (AX CDT 2). The specificity at the same level of alcohol consumption, markedly differed between the two methods: 92%, 76% and 90% for CDTect, AX CDT 1 and AX CDT 2, respectively. The variation coefficient (day-to-day) was 10%, 22% and 10% for CDTect, AX CDT 1 and AX CDT 2, respectively.

Carbohydrate-deficient transferrin and other markers of high alcohol consumption: a study of 502 patients admitted consecutively to a medical department

An isoform of transferrin, carbohydrate-deficient transferrin (CDT) is increased in a high percentage of abusing alcoholics and has been found superior in its specificity compared with other biological markers. We used serum CDT as a screening parameter in 502 patients consecutively admitted to our medical department during a 4-week period. The intake of ethanol during the last 4 weeks was registrated by personal interviews and the mean daily consumption calculated. Serum CDT was measured at admission (CDTect) and compared with gamma-glutamyltranspeptidase (GGT), AST, ALT, and mean corpuscular volume (MCV). Serum CDT detected 18 of 26 (69%) patients who consumed > 50 g ethanol daily. The clinical sensitivity of CDT of detection ethanol consumption > 50 g daily was 69%, compared with 73%, 50%, 35%, and 52% for increased values of GGT, AST, ALT, and MCV, respectively. Altogether, 38 of 476 patients (8%) with a daily ethanol consumption < 50 g also had increased serum CDT levels. The specificity of CDT was 92%, compared with 75%, 82%, 86%, and 85% for GGT, AST, ALT, and MCV, respectively. In the 60 patients who consumed > 10 g ethanol daily, we found a significantly positive correlation between CDT and ethanol consumption (r = 0.52, p < 0.001). A positive correlation was also found between serum transferrin and CDT (r = 0.51, p < 0.001). In conclusion, the specificity of CDT is much higher compared with GGT in detecting alcohol abuse. Some acute and chronic illnesses may increase the serum level of CDT. False-positive CDT levels may be caused by changes in serum transferrin concentration.

The effect of iron overload and iron reductive treatment on the serum concentration of carbohydrate-deficient transferrin

The concentration of carbohydrate-deficient transferrin in serum (CDT) has been used as a reliable indicator of recent alcohol consumption. We have investigated the utility of this laboratory test in 20 patients with hereditary haemochromatosis (HH) by simultaneous evaluation of serum concentrations of liver transaminases, gamma-glutamyl transpeptidase, iron, transferrin and assessment of the liver iron concentration by magnetic resonance imaging. 11 patients were re-examined during iron depletion with phlebotomies. In all 11 patients intensive but not maintenance iron removal was associated with an increase in serum CDT, in three patients even to levels above the reference range. The mean serum CDT increased from 8.5 (SD 2.2) U/l to 16.6 (SD 7.2) U/l (P < 0.001). Iron mobilization from the liver was found particularly responsible for the increase in serum CDT. Independent of this finding we found a significant semi-logarithmic correlation (r = -0.77, P = 0.009) between the MRI determined liver iron concentration and serum CDT in the patients not on iron depletion. Our findings indicate that the utility of serum CDT as a measure of alcohol consumption in patients with HH may be compromised, especially during intensive iron depletion.

Carbohydrate-deficient transferrin as a measure of immoderate drinking: remaining issues

A growing body of investigations demonstrate that elevated levels of carbohydrate-deficient transferrin (CDT) effectively distinguishes alcoholics recently consuming large amounts of alcohol from light social drinkers or teetotalers. Nevertheless, important questions still remain concerning the value of CDT as a more generalized marker of alcohol consumption. Most important, the nature of the drinking pattern, including quantity and frequency, necessary to raise levels of CDT significantly remains unclear. Neither has research convincingly demonstrated that CDT is as accurate a marker for women, young adults, or non-Caucasian ethnic groups as for White, middle-aged men. Whereas CDT might serve as a useful outcome measure in trials of alcoholism treatment effectiveness, current research suggests that CDT is of limited value in identifying problematic drinking in general medical or community settings in which a broad continuum of drinkers is represented. Combining CDT with other biochemical or self-report screening measures may, however, improve sensitivity in these contexts. At present, the most accurate laboratory technique to detect CDT seems to be isoelectric focusing. Additional research, however, is needed to resolve the issue of whether CDT is best quantitated as a simple value or if its ratio to total transferrin or non-CDT results in higher predictive validity.

Monosaccharide composition of haptoglobin in liver diseases and alcohol abuse: large changes in glycosylation associated with alcoholic liver disease

Liver damage through prolonged intake of high amounts of alcohol is a serious problem that affects many members of the population. The aim of this study was to investigate changes in the glycosylation of haptoglobin (Hp) resulting from alcoholic liver diseases. The monosaccharide composition was measured in Hp isolated from 48 healthy individuals, 15 alcohol abusers (AA); 25 patients with alcoholic liver disease, including those with alcoholic cirrhosis (ALD/AC), and 17 other patients with either chronic active hepatitis (AH) or primary biliary cirrhosis (BC). Fucose was elevated per mol of Hp in 70%, 44%, and 33% of the individuals in the ALD/AC, BC and AA groups, respectively. Fucose was not elevated in the AH group. N-acetylglucosamine was also elevated in the ALD/AC group. Expressing results per 3 mol of mannose suggested the presence of higher branching with increased fucose content in Hp from all the abnormal groups except the AH group. More structural information is required to develop the diagnostic potential of carbohydrate measurements of Hp in alcoholic liver diseases.