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

Detection and Quantification of Carbohydrate-Deficient Transferrin by MALDI-Compatible Protein Chips Prepared by Ambient Ion Soft Landing

BACKGROUND

Transferrin is synthetized in the liver and is the most important iron-transport carrier in the human body. Severe alcohol consumption leads to alterations in glycosylation of transferrin. Mass spectrometry can provide fast detection and quantification of transferrin isoforms because they have different molecular masses. In this study, we used antibody chips in combination with MALDI-TOF MS for the detection and quantification of transferrin isoforms.

METHODS

Protein chips were prepared by functionalization of indium tin oxide glass using ambient ion soft landing of electrosprayed antitransferrin antibody. Two microliters of patient serum was applied on the antibody-modified spots, and after incubation, washing, and matrix deposition, transferrin isoforms were detected by MALDI-TOF MS. Peak intensities of each transferrin form were used to calculate total carbohydrate-deficient transferrin (CDT). The CDT values obtained by the MALDI chip method were compared with the results obtained by a standard capillary electrophoresis (CE).

RESULTS

The chip-based MALDI-TOF MS method was used for enrichment and detection of CDT from human serum. A sample cohort from 186 patients was analyzed. Of these samples, 44 were positively identified as belonging to alcoholic patients, whereas 142 were negative by the MALDI chip approach. The correlation of the data obtained by the CE and the chip-based MALDI was r = 0.986, 95% CI.

CONCLUSIONS

Functionalized MALDI chips modified by antitransferrin antibody prepared by ambient ion soft landing were successfully used for detection and quantification of CDT from human sera.

Psychiatric Comorbidity and Physical Correlates in Alcohol-dependent Patients

AIM

To examine the prevalence and pattern of comorbidity in alcohol dependence and its relationship with physical and laboratory findings.

MATERIALS AND METHODS

Eighty males with alcohol dependence were examined using the Hindi version of Diagnostic Interview for Genetic Studies, the International Classification of Disease-10^th Edition Personality Disorder Examination, Alcohol Use Disorder Identification Test for alcohol use, global assessment of functioning, blood sampling electrocardiogram, and ultrasonogram.

RESULTS

Eighty-seven percent had a comorbid Axis I or an Axis II psychiatric disorder, over 78% had nicotine dependence, and 56% had comorbid Axis II disorder, antisocial personality being the most common. Gamma glutamyl transpeptidase levels were significantly associated with comorbidity.

CONCLUSIONS

High comorbidity of Axis I psychiatric disorders was found among persons with alcohol dependence. Axis II disorders were also present.

Liver Transplantation for Alcohol-Related Liver Disease

Alcoholic liver disease (ALD) is a common indication for liver transplantation. It is a much debated indication for deceased donor liver transplantation due to organ shortage and potential of alcohol relapse after liver transplantation. A six-month abstinence before liver transplantation is required at most centers to decrease chances of alcohol relapse after liver transplantation. However, this rule is not relevant for patients with severe alcoholic hepatitis or severely decompensated patients who are unlikely to survive till 6 months. Long-term care of these patients after liver transplantation includes assessment of relapse, smoking, and surveillance of de novo malignancies. Current review discusses role of abstinence, factors affecting alcohol relapse, liver transplantation for alcoholic hepatitis, role of living donor liver transplantation, and long-term care of ALD patients who undergo liver transplantation.

Zonisamide, topiramate, and levetiracetam: efficacy and neuropsychological effects in alcohol use disorders

The anticonvulsant topiramate not only decreases ethanol consumption in alcohol dependence (AD) but also may produce several adverse events including cognitive impairment. Zonisamide is a structurally related anticonvulsant that is a promising agent for the treatment of AD and may have greater tolerability than topiramate. This study evaluated the effects of zonisamide (400 mg/d) on alcohol consumption and its neurotoxic effects in subjects with AD. A double-blind placebo-controlled clinical trial was conducted using 2 comparator anticonvulsant drugs, topiramate (300 mg/d) and levetiracetam (2000 mg/d), which does not impair cognition. Study medications were administered for 14 weeks, including a 2-week taper period. Medication adherence was facilitated using Brief Behavioral Compliance Enhancement Treatment. The neurotoxicity of the study drugs was assessed using neuropsychological tests and the AB-Neurotoxicity Scale. Compared with placebo, both zonisamide and topiramate produced significant reductions in the drinks consumed per day, percent days drinking, and percent days heavy drinking. Only the percent days heavy drinking was significantly decreased in the levetiracetam group. The topiramate cell was the only group that had a significant increase on the mental slowing subscale of the Neurotoxicity Scale compared with placebo at study weeks 11 and 12. Topiramate and zonisamide both produced modest reductions in verbal fluency and working memory. These findings indicate that zonisamide may have efficacy in the treatment of AD, with effect sizes similar to topiramate. Both of these drugs produced similar patterns of cognitive impairment, although only the topiramate group reported significant increases in mental slowing.

Assessing the drinking status of liver transplant patients with alcoholic liver disease

The accurate assessment of drinking by patients with alcoholic liver disease is important both before and after liver transplantation. Unfortunately, self-reports by these individuals often underestimate their actual alcohol consumption. Several recently developed biochemical measures can provide additional information on a patient's use of alcohol. This article describes ethyl glucuronide, ethyl sulfate, phosphatidyl ethanol, and carbohydrate-deficient transferrin as biomarkers of drinking and summarizes research dealing with their application in patients with alcohol use disorders who are candidates for or recipients of liver transplantation. The article also offers suggestions for enhancing the reliability of self-report measures of drinking status.

Relationships between the Level of Alcohol Consumption and Abnormality in Biomarkers According to Facial Flushing in Korean Male Drinkers

BACKGROUND

This research investigated the association between facial flushing after drinking and alcohol-induced biomarker abnormalities.

METHODS

This retrospective study included 374 male drinkers who visited the department of Family Medicine of Chungnam National University Hospital between January and December of 2010. The participants were classified into two groups: the flushing group (n = 107) and the non-flushing group (n = 267). The biomarkers assessed were % carbohydrate-deficient transferrin (CDT) and gamma glutamyl transferase (rGTP). The upper limits of %CDT and rGTP were set as 2.47 and 50, respectively. The receiver operating characteristic (ROC) curve was used to obtain the cut-off value for the amount of drinking that caused abnormal %CDT and rGTP levels in the two groups. The sensitivity and specificity of the cut-off drinking amount for %CDT and rGTP abnormalities were analyzed in each group.

RESULTS

In the flushing group, the cut-off value for alcohol-induced %CDT abnormality was 3.38 drinks (1 drink: 14 g of alcohol) per week, with sensitivity of 77.8% and specificity of 70.4%. In the non-flushing group, the cut-off value was 11.25 drinks per week, with sensitivity of 62.2% and specificity of 69.6%. The cut-off value for the amount of alcohol that induced rGTP abnormality was 3.38 drinks per week in the flushing group, with sensitivity of 68.0% and specificity of 76.8%, whereas it was 8.75 drinks in the non-flushing group, with sensitivity of 71.1% and specificity of 66.7%. The area under the ROC of the drinking level was 0.726 in the flushing group and 0.684 in the non-flushing group for %CDT. For rGTP, the value was 0.738 in the flushing group and 0.718 in the non-flushing group.

CONCLUSION

The weekly drinking amount required to induce biomarker abnormalities was lower in the flushers than in the non-flushers.

Alcohol biomarkers in applied settings: recent advances and future research opportunities

During the past decade, advances have been made in the identification, development, and application of alcohol biomarkers. This is important because of the unique functions that alcohol biomarkers can serve in various applied settings. To carry out these functions, biomarkers must display several features including validity, reliability, adequacy of temporal window of assessment, reasonable cost, and transportability. During the past two decades, several traditional alcohol biomarkers have been studied in multiple human studies. Meanwhile, several new, promising biomarkers, including various alcohol metabolites and alcohol biosensors, are being explored in human studies. In addition, researchers have explored using biomarkers in combination and using biomarkers in combination with self-reports, resulting in increased sensitivity with little sacrifice in specificity. Despite these advances, more research is needed to validate biomarkers, especially the new ones, in humans. Moreover, recent advances in high-throughput technologies for genomics, proteomics, and metabolomics offer unique opportunities to discover novel biomarkers, while additional research is needed to perfect newly developed alcohol sensors. Development of more accurate biomarkers will help practicing clinicians to more effectively screen and monitor individuals who suffer from alcohol use disorders.

Are biomarkers of chronic alcohol misuse useful in the assessment of DWI recidivism status?

A first driving while impaired by alcohol (DWI) conviction is a key opportunity to identify offenders who are at high risk for recidivism. Detection of alcohol use disorder (AUD) is a major target of current DWI assessments. However, offenders frequently underreport their alcohol consumption, and use of biomarkers has been proposed as a more objective indicator. Among the best established are aspartate aminotranferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), mean corpuscular red blood cell volume (MCV), carbohydrate-deficient transferrin (CDT), and thiamine. To our knowledge, no research has directly verified whether AUD biomarkers predict DWI recidivism status. Using a cross-sectional design, this study tested three hypotheses related to the utility of biomarkers in DWI assessment.

HYPOTHESES

(1) DWI recidivists possess biomarkers indicative of greater prevalence of AUD compared to first-time offenders; (2) multiple biomarkers better differentiate first-time offenders from recidivists compared to individual biomarkers; and (3) biomarkers add significantly to the prediction of recidivism over and above psychosocial questionnaires.

METHODS

First-time offenders (n = 49) and recidivists (n = 95) participated in the study. In addition to self-reported information on sociodemographic and driving characteristics, data from several AUD questionnaires were gathered: Michigan Alcoholism Screening Test, Alcohol Use Disorders Identification Test, Composite International Diagnostic Interview, and Timeline Follow-Back. Blood samples were collected to measure AST, ALT, GGT, MCV, CDT, and thiamine.

RESULTS

AUD biomarkers, taken individually or in combination, did not indicate that recidivists had more frequent AUD compared to first-time offenders. Also, they failed to significantly differentiate first-time offenders from recidivists or predict recidivism status. Finally, the superiority of biomarkers over psychosocial AUD questionnaires was not supported in the laboratory setting.

CONCLUSION

The present findings suggest that biomarkers of chronic patterns of heavy drinking may not be adequate to capture the multiple processes that appear to promote recidivism (e.g., binge drinking, other risky behavioural and personality features). Despite their objectivity, caution is warranted in the interpretation of a positive score on these biomarkers in DWI assessment. Longitudinal research is needed to more comprehensively explore the relationship between positive biomarkers in first-time offenders and their risk of becoming recidivists.

The Bayesian Alcoholism Test had better diagnostic properties for confirming diagnosis of hazardous and harmful alcohol use

OBJECTIVE

Conventional tests for alcoholism fail to confirm hazardous and harmful alcohol use (HHAU) accurately and objectively. We validated a Bayesian Alcoholism Test (BAT) for confirming the diagnosis of HHAU.

STUDY DESIGN AND SETTING

BAT is based on studies on the prevalence of HHAU and other diseases causing similar abnormalities, and on conditional probabilities of these disorders and associated biochemical markers and clinical signs. BAT was compared to carbohydrate-deficient transferrin (CDT) and gamma-glutamyltransferase (GGT) in treatment-seeking alcoholics, non-treatment-seeking heavy drinkers, and controls. Main outcome measures were test sensitivity and specificity, likelihood ratios, and receiver-operating characteristic (ROC) curves.

RESULTS

Comparing alcoholics and controls, sensitivity of BAT (94%) was significantly higher than CDT (63%) and GGT (73%). The area under the ROC curve for BAT (.989) was significantly higher than the area under the curve for CDT (.909) and area under the curve for GGT (.902). Using pooled data of all 182 subjects included in the study, the amount of drinking had a significant better correlation coefficient with BAT (.795) than with CDT (.657), and GGT (.604).

CONCLUSION

BAT has better diagnostic properties than CDT and GGT for confirming HHAU.

Carbohydrate-deficient transferrin and gamma-glutamyl transpeptidase in the evaluation of alcohol consumption

OBJECTIVE

Carbohydrate-deficient transferrin has been proposed to be useful in evaluating alcohol consumption but there is no consensus on its use in routine practice. The aim of this retrospective study was to compare carbohydrate-deficient transferrin and gammaglutamyl transpeptidase assays for the evaluation of alcohol consumption.

METHODS

Six hundred thirty-three outpatients attending one outpatient care center were included in this study. Patients were divided into five categories according to alcohol consumption: category 1 included non-weaned patients drinking more than 30 g/day for women and more than 50 g/day for men, category 2 included relapse patients, category 3 included moderate drinkers, category 4 included patients weaned less than one month, and category 5 included patients weaned more than one month. One experienced physician estimated alcohol intake from patient declarations during a face-to-face interview.

RESULTS

Sensitivity of carbohydrate-deficient transferrin varied, depending on patient category, from 32% to 92% versus 41% to 72% for gamma-glutamyl transpeptidase. Specificity of carbohydrate-deficient transferrin varied from 71% to 96% versus 23% to 62% for gamma-glutamyl transpeptidase. After one month of abstinence, specificity of carbohydrate-deficient transferrin was 62% versus 19% for gamma-glutamyl transpeptidase.

CONCLUSION

This study confirms that carbohydrate-deficient transferrin is more accurate in predicting alcohol consumption compared with gamma-glutamyl transpeptidase in alcoholic outpatients.

Recent advances in the pharmacotherapy of alcoholism

Alcoholism is a devastating illness that leads to great societal losses. Despite significant health consequences, there are few medically based treatments for alcoholism. During the past decade, a better understanding of the neuroscientific underpinnings of addiction has led to the use of novel pharmacotherapeutic treatments for alcoholism. In particular, there have been new developments in the understanding of the involvement of the dopamine, opiate, serotonin, gamma-aminobutyric acid, and glutamate neurotransmitter systems in the pathophysiology of alcohol withdrawal, alcohol dependence, and in subtypes of individuals with alcoholism. In this article, new developments in the pharmacotherapy of alcohol dependence will be reviewed. In particular, the use of anticonvulsants in alcohol withdrawal and protracted abstinence syndromes will be discussed. Data on naltrexone, acamprosate, and topiramate will be highlighted. In addition, data concerning the use of serotonin reuptake inhibitors in subtypes of alcoholism and the use of combination pharmacotherapy will be reviewed.

Multicenter Validation Study of the %CDT TIA Kit in Alcohol Abuse and Alcohol Dependence

BACKGROUND

Carbohydrate-deficient transferrin (CDT) and gamma-glutamyl transferase (GGT) are used as biomarkers of alcohol misuse. The aim of this study was to evaluate, in terms of sensitivity and specificity, the performance of the new Bio-Rad %CDT TIA kit and GGT assay for identifying alcohol abuse and alcohol dependence (according to the DSM-IV criteria).

METHODS

An open multicenter study (30 centers) over 3 months, including patient groups of "abusers," "dependents," and controls, was conducted in France.

RESULTS

In alcohol abuse, the sensitivity of GGT was 0.56, and that of CDT was 0.80; in alcohol dependence, the sensitivity of GGT was 0.86, and that of CDT was 0.91. The specificity of GGT was 0.77, and that of CDT was 0.83. The association of GGT with CDT increased sensitivity for alcohol abuse to 0.90 and for alcohol dependence to 0.99, but it appreciably decreased specificity (0.63).

CONCLUSIONS

%CDT is the better screening marker for alcohol abuse and dependence, but GGT is still a useful marker for the detection of alcohol dependence. As an assay method, the second-generation Bio-Rad %CDT immunoassay can be recommended for routine CDT measurement.

Potential Drug Interactions with the Percent Carbohydrate-Deficient Transferrin (%CDT) Test, a New Alcohol Biomarker

STUDY OBJECTIVE

To determine the effects of drugs on levels of carbohydrate-deficient transferrin (CDT), using the %CDT test, a new alcohol biomarker, in patients receiving drug therapy for chronic medical conditions such as diabetes mellitus, hypertension, and lipid disorders.

DESIGN

Regression analysis of transformed data.

SETTING

Eight primary care clinics in central Wisconsin.

PATIENTS

Seven hundred ninety-nine primary care patients who were prescribed drug therapy for a variety of chronic illnesses such as diabetes, hypertension, and lipid disorders.

MEASUREMENTS AND MAIN RESULTS

The %CDT level, 30-day history of alcohol consumption, symptoms of alcohol abuse or dependence, health status, and prescribed drugs were determined for each patient. All prescribed drugs that were taken by the patients in the last month were determined by self-report, medical records, or pharmacy records. Of the 799 patients, 89 were receiving drug therapy for diabetes, 299 for hypertension, 209 for both diabetes and hypertension, and 202 for medical conditions other than diabetes or hypertension. A regression analysis was performed after the data were transformed. Alcohol consumption, sex, age, tobacco use, and 20 drug classes were entered into the model. Factors associated with increased %CDT levels were alcohol consumption, female sex, and bupropion use. Two additional drug classes, the angiotensin II receptor blockers and the tricyclic antidepressants, were associated with lower %CDT levels. The effects of bupropion and tricyclic antidepressants on %CDT levels, however, appear to be confounded by alcohol intake.

CONCLUSION

This study suggests that only one of 20 drug classes-the angiotensin II receptor blockers-affected %CDT levels in our primary care sample. Additional research with larger samples is needed to focus on the effects of individual drugs used in general clinical settings on %CDT levels.

The use of biological laboratory markers in the diagnosis of alcohol misuse: an evidence-based approach

BACKGROUND

A large number of patients seen in clinical practice have an underlying alcohol problem. There is a pressing need for accurate methods to diagnose alcohol over-consumption objectively. Our aim was to determine how best to use biological markers to objectify alcohol problems in patients with clinical suspicion of alcohol misuse.

METHODS

A 6-month longitudinal multicenter trial was conducted, using four study groups (alcohol abusers, alcohol-dependents, healthy controls and consulting controls). CDT, GGT and MCV were measured. Statistical analyses used a computer learning system that created classification systems displayed in decision trees.

RESULTS

In 379 subjects the marker that best discriminated those with alcohol problems from controls was CDT. GGT then helped to differentiate between alcohol abuse and alcohol dependence in cases of high CDT. MCV, age and gender provided no extra information.

DISCUSSION

We recommend CDT as a first-line biological marker to confirm or disprove suspected alcohol misuse. High CDT plus GGT above normal points to alcohol dependence, while high CDT plus GGT below normal is evidence of alcohol abuse.

The future of proteomics in the study of alcoholism

This article represents the proceedings of a workshop at the 2003 annual meeting of the Research Society on Alcoholism in Fort Lauderdale, FL. The workshop organizers/chairpersons were Chinnaswamy Kasinathan and Paul Manowitz. The presentations were (1) Introduction to the field of proteomics, by Kent Vrana; (2) Use of proteomics in the identification of urinary biomarkers for alcohol intake, by Chinnaswamy Kasinathan, Paul Thomas, and Paul Manowitz; (3) Proteomics screening illuminates ethanol-mediated induction of HDL proteins in macaques, by Kent Vrana, Randy Gooch, Travis Worst, Stephen Walker, Aaron Xu, Peter Pierre, Heather Green, and Kathleen Grant; and (4) Proteomics applied to the study of the liver, by Laura Beretta.

Advances in alcoholic liver disease

Alcoholic liver disease (ALD) remains a major cause of morbidity and mortality worldwide. For example, the Veterans Administration Cooperative Studies reported that patients with cirrhosis and superimposed alcoholic hepatitis had a 4-year mortality of >60%. Interactions between acetaldehyde, reactive oxygen and nitrogen species, inflammatory mediators and genetic factors appear to play prominent roles in the development of ALD. The cornerstone of therapy for ALD is lifestyle modification, including drinking and smoking cessation and losing weight, if appropriate. Nutrition intervention has been shown to play a positive role on both an inpatient and outpatient basis. Corticosteroids are effective in selected patients with alcoholic hepatitis and pentoxifylline appears to be a promising anti-inflammatory therapy. Some complementary and alternative medicine agents, such as milk thistle and S-adenosylmethionine, may be effective in alcoholic cirrhosis. Treatment of the complications of ALD can improve quality of life and, in some cases, decrease short-term mortality.

The analysis of carbohydrate-deficient transferrin, marker of chronic alcoholism, using capillary electrophoresis

Carbohydrate-deficient transferrin (CDT) is currently considered to be the best available marker for the diagnosis of chronic alcoholism. A large variety of methods have been developed, demonstrating the need for standardisation. Commercially available anion-exchange chromatographic-based assays are easy to use and require no specialised, expensive instruments. However, these methods cannot identify genetic transferrin variants or the carbohydrate-deficient glycoprotein syndrome. In 1989, a capillary isoelectric focusing method was developed for quantitative measurement of CDT. Despite the optimal resolution, this method is not easily applied in a clinical routine environment due to the complexity of analysis. Capillary electrophoresis in a polymer network using coated capillaries allowed full resolution of the sialoforms of human transferrin. The drawbacks due to an expensive and time-consuming sample preparation were eliminated when a method in neat serum was developed. Capillary zone electrophoresis allowed full resolution of the transferrin isoforms with a high analytical performance in a short analysis time thanks to a strong electroosmotic flow. Genetic transferrin variants were easily detected, avoiding false-positive results. Also, using capillary zone electrophoresis, it was shown that CDT is a suitable marker of chronic alcohol abuse detection in transferrin CD (common/cathodal) variants.

Late onset alcoholism

Rather high prevalence rates of alcohol abuse in the elderly have been reported in the literature. However, there is some evidence that many elderly persons with alcohol problems are not identified, probably due to the nonspecificity of alcohol-related presentations in old individuals. Thus, there is an ongoing discussion on appropriate diagnostic criteria for alcohol dependence in elder people who frequently begin to abuse alcohol in late life. This study was aimed to explore whether alcoholics with late onset (beginning after the age of 45) differ from those with an early onset (prior the age of 25). Two hundred and sixty eight subjects consecutively referred to a ward of a general hospital specialized for alcohol detoxification were divided into three groups by the age at onset of harmful alcohol consumption. The duration of harmful drinking was rather similar in all groups. However, alcohol dependence according to the ICD-10 criteria (three or more have to be fulfilled) was diagnosed in 94.1% of the alcoholics with an early onset (</= 25 years), but only in 62.2% of those with late onset (P < 0.0001). Significant differences between these groups were found for the following criteria: preoccupation with drinking (P < 0.0001), impaired capacity to control drinking (P < 0.01), strong desire to drink alcohol (P < 0.01), and a trend towards a lower rate of lifetime psychiatric comorbidity. The alcoholics with late onset reported fewer previous detoxifications and a lower actual alcohol consumption. Moreover, they showed a higher rate of abstinence in the 12 month follow-up. Regarding the difficulties in comparing groups of different ages at onset of harmful alcohol use our results suggest that the alcoholics with late onset differ in many ways from those with early onset.

Biomarkers as aids to identification of relapse in alcoholic patients

Since return to drinking is common in patients recovering from alcoholism, recognition of relapse should be an important component of treatment. Recurrent assessment with biochemical measures can provide clinicians with useful information on the drinking status of their patients. This chapter addresses issues surrounding the importance of early detection of relapse, describes biochemical markers that may assist in this, reviews relevant scientific investigations, and offers recommendations to researchers and clinicians.

Carbohydrate-deficient transferrin and gamma-glutamyltransferase for the detection and monitoring of alcohol use: results from a multisite study

BACKGROUND

The purpose of this article is to evaluate the biological marker of heavy alcohol use, carbohydrate-deficient transferrin (CDT), in contrast to the older and more widely used gamma-glutamyltransferase (GGT) for the detection and monitoring of heavy alcohol use.

METHODS

In this report, CDT and GGT sensitivity and specificity for heavy alcohol intake are examined in a large multisite study in which 444 recently admitted inpatient alcoholics were compared with 204 matched social drinker controls. In addition, changes in these biomarkers were evaluated during an initial abstinence period and biweekly over 14 weeks of monitoring to compare changes in CDT and GGT during continued abstinence or relapse.

RESULTS

CDT and GGT were comparable in identifying heavy alcohol consumption in men, but GGT appeared to be better for women. For both genders, when these markers were combined, there was better sensitivity than when used alone. CDT and GGT both decreased during 4 weeks of abstinence. When we used a 30% increase from baseline abstinent levels as an indicator, CDT appeared marginally better than GGT at indicating relapse in men but not in women. For men in particular, relapse over the course of the study was best identified by evaluating changes (30% increase) in both markers simultaneously.

CONCLUSIONS

These results support the utility of CDT, especially when used in conjunction with GGT, as an aid in detecting and monitoring heavy alcohol consumption.

Biochemical markers of alcohol use in pregnant women

OBJECTIVES

To describe the serious health consequences of alcohol (ethanol) use, especially as they relate to pregnancy and the development of fetal alcohol syndrome (FAS) and fetal alcohol effects (FAE). The classic markers of alcohol exposure, including blood/breath alcohol, gamma-glutamyl transferase (gammaGT), mean corpuscular volume (MCV), hemoglobin-associated acetaldehyde (HAA) and carbohydrate deficient transferrin (CDT), are valuable and their methods of analysis are reviewed.

CONCLUSIONS

Since both FAS and FAE represent two of the leading preventable causes of mental retardation and birth defects, identification of alcohol use early in pregnancy is important to avoid adverse fetal outcomes. Unfortunately, the diagnosis of FAS and FAE is usually made after birth, when alcohol damage has become irreversible and permanent. The clinical laboratory can help prevent this damage and make a valuable contribution in assessing prenatal alcohol use. The clinical utility of blood/breath alcohol, gammaGT, MCV, HAA and CDT in alcohol use identification, especially in pregnancy, is substantial. Although none of the markers singularly has adequate sensitivity and specificity for screening, their diagnostic utility increases when measured as a panel. This is especially true in detecting alcohol use in pregnancy where the presence of several positive markers was correlated with the presence of alcohol-related fetal effects.

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 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 for detection and monitoring of sustained heavy drinking. What have we learned? Where do we go from here?

Carbohydrate-deficient transferrin (CDT) has been widely investigated as a biological marker of heavy alcohol consumption. In general, it has been found to be at least as sensitive and probably more specific than gamma-glutamyltransferase (GGT). Because the two analytes are not highly correlated, their use in parallel enhances the sensitivity of detection of heavy alcohol consumption, especially in clinical populations. Women as a group produce more CDT under natural conditions and may produce less CDT in response to heavy drinking. Carbohydrate-deficient transferrin has found a place in the monitoring of alcoholics during treatment. Changes in CDT levels from individualized baseline values seem to be more sensitive to lower level relapse drinking than is the use of raw cut-off values. There are some conditions such as severe liver disease in which higher than normal levels of CDT are produced, thereby reducing the specificity of this marker for detecting heavy drinking under certain conditions. Future directions for the use of CDT include standardization and automation of measurement technology, evaluation of how to use it wisely in myriad medical and institutional settings, understanding more thoroughly the gender issues in its production, and greater evaluation of its performance as a monitoring tool during treatment and follow-up situations. How to combine CDT with both verbal tools of alcohol assessment and newer biological markers will also need more extensive evaluation.

The role of biomarkers in alcoholism medication trials

BACKGROUND

Increasingly, biomarkers are being incorporated into the research design of clinical trials on medications to reduce drinking in alcoholics. To date, however, there has been little analysis of the unique roles that biomarkers can play in such investigations or of the practical and conceptual considerations that surround their best use in this context.

METHODS

Clinical trials of alcoholism medications published between 1985 and the present were abstracted to determine how biomarkers were used and how changes in them related to self-report measures of drinking.

RESULTS

Six uses of biomarkers were identified: determination of subjects to be included or excluded in the trial; description of baseline sample characteristics; primary and secondary outcome assessment; corroboration of self-reports of drinking status; specification of patients likely to respond to the medication; and evaluation of drug safety.

CONCLUSION

Use of biomarkers in such studies appears warranted, particularly as an objective source of information on treatment efficacy that can be considered with patient self-report measures of drinking status. Biomarkers related to liver functioning also can assist in determination of drug safety for medications metabolized by the liver.

Gamma glutamyl transferase

Serum gamma-glutamyl transferase (GGT) has been widely used as an index of liver dysfunction and marker of alcohol intake. The last few years have seen improvements in these areas and advances in understanding of its physiological role in counteracting oxidative stress by breaking down extracellular glutathione and making its component amino acids available to the cells. Conditions that increase serum GGT, such as obstructive liver disease, high alcohol consumption, and use of enzyme-inducing drugs, lead to increased free radical production and the threat of glutathione depletion. However, the products of the GGT reaction may themselves lead to increased free radical production, particularly in the presence of iron. There have also been important advances in the definition of the associations between serum GGT and risk of coronary heart disease, Type 2 diabetes, and stroke. People with high serum GGT have higher mortality, partly because of the association between GGT and other risk factors and partly because GGT is an independent predictor of risk. This review aims to summarize the knowledge about GGT's clinical applications, to present information on its physiological roles, consider the results of epidemiological studies, and assess how far these separate areas can be combined into an integrated view.

The early detection of alcohol consumption (EDAC) score in the identification of Heavy and at-risk drinkers from routine blood tests

The objective of this study was to use the EDAC score to detect heavy and at-risk drinking in young adults (mean age = 25 years) and compare the results to self-reports. The EDAC score is a linear discriminant function (LDF) derived from the analysis of a combination of up to 35 blood chemistry and hematology analytes ordered routinely in clinical settings. Subjects (N = 150) were recruited from medical care facilities at the University of Missouri, Columbia. Blood samples, obtained from males (N = 66) and females (N = 84), were sent to LabCorp (Burlington, NC) for analysis. The blood chemistry panels were evaluated using a Linear Discriminant Function method available through SPSS software to predict whether each individual was a Heavy Drinker or an At-Risk Drinker. Heavy Drinkers consumed on average > or = 4 drinks daily for males and > or = 3 drinks daily for females. At-Risk Drinkers consumed at least 14 drinks per week or drank more than 4 drinks on any occasion in the last 14 days if male and consumed at least 7 drinks per week or more than 3 drinks on any occasion if female. Not-Heavy Drinkers and Not-At-Risk Drinkers consumed less than the amounts above. The results showed 8/10 (80%) males and 2/2 women identified as Heavy Drinkers by both the EDAC score (prior probability Not-Heavy vs. Heavy Drinker = 0.5:0.5) and self-report. Fifty of 56 (89%) males and 65/82 (79%) of females were identified as Not-Heavy Drinkers by both EDAC score and self-report. There were 6/54 (11%) males and 15/82 (18%) women with false positive results, of these, 14/21 (67%) met dependence criteria by DSM-IV. The EDAC test showed 30% sensitivity and 96% specificity when identifying At-Risk drinking males and 42% sensitivity and 90% specificity when identifying At-Risk drinking females. In females, the EDAC's sensitivity was higher than any single traditional or new laboratory marker previously reported for diagnosis of alcohol abuse such as GGT, MCV and CDT. As a complement or a substitute to an interview, in subjects who are less candid about their drinking, the EDAC is a useful tool to assess heavy and at-risk alcohol consumption in young adults.

Association of carbohydrate-deficient transferrin (CDT) and gamma-glutamyl-transferase (GGT) with serum lipid profile in the Finnish population

BACKGROUND

Moderate consumption of alcohol may reduce mortality from vascular diseases. The beneficial effects of alcohol may partly be mediated by its effects on lipoprotein metabolism. We studied the connection between alcohol consumption and the serum lipid profile from a well-documented national health program study.

METHODS AND RESULTS

Carbohydrate-deficient transferrin (CDT) and gamma-glutamyl-transferase (GGT) were used as biochemical markers for alcohol consumption. The laboratory analyses were carried out on 5675 subjects (3097 males and 2578 females). The subjects were divided into quartiles on the basis of CDT or GGT value. The highest CDT quartile and the lowest GGT quartile seemed to be associated with a favorable lipid profile and the lowest CDT quartile and the highest GGT quartile were associated with an unfavorable lipid profile. Serum high density lipoprotein (HDL) cholesterol values were significantly higher and triglycerides lower with increasing serum CDT concentrations for both men and women. Increasing serum GGT was associated with higher serum total cholesterol and higher triglycerides in both men and women and lower HDL cholesterol in men.

CONCLUSIONS

CDT and GGT seem to detect different populations of subjects in regard to lipid metabolism. These observations may lead to a better understanding of the effects of alcohol consumption on lipids as well as mechanisms behind favorable and detrimental effects of alcohol on vascular diseases.

CONDENSED ABSTRACT

Carbohydrate-deficient transferrin (CDT) and gamma-glutamyl-transferase (GGT) were used as biochemical markers for alcohol consumption. A total of 3097 males and 2578 females were divided into quartiles on the basis of their CDT or GGT values. The highest CDT quartiles had higher HDL and lower triglycerides, whereas the highest GGT quartiles appeared to be associated with higher total cholesterol and triglycerides in both genders and lower HDL in men. CDT and GGT seem to detect different populations of subjects in regard to lipid metabolism. These observations may have important clinical and public health implications.

The role of laboratory tests in alcoholism treatment

Although assessment in the field of alcoholism treatment is generally verbal in nature, biological tests can also provide counselors and program evaluators useful and unique information. Five such laboratory measures are briefly described, with particular emphasis on carbohydrate deficient transferrin, a biomarker recently approved by the FDA. Applications for laboratory tests in alcohol screening, motivating patients, and monitoring treatment progress are also proposed.

Carbohydrate-deficient Transferrin as a Marker of Chronic Alcohol Abuse: A Critical Review of Preanalysis, Analysis, and Interpretation

Background: Carbohydrate-deficient transferrin (CDT) is used for diagnosis of chronic alcohol abuse. Some 200–300 reports on CDT have been published in impact factor-listed journals. The aims of this review were to condense the current knowledge and to resolve remaining issues on CDT.

Approach: The literature (1976–2000) was searched using MEDLINE and Knowledge Server with “alcohol and CDT” as the search items. The data were reviewed systematically, checked for redundancy, and organized in sequence based on the steps involved in CDT analysis.

Content: The review is divided into sections based on microheterogeneity of human serum transferrin (Tf), definition of CDT, structure of human serum CDT, pathomechanisms of ethanol-induced CDT increase, preanalysis, analysis, and medical interpretation (postanalysis). Test-specific cutoff values for serum CDT and causes of false positives and negatives for chronic alcohol abuse are discussed and summarized.

Summary: Asialo- and disialo-Fe2-Tf, which lack one or two complete N-glycans, and monosialo-Fe2-Tf (structure remains unclear) are collectively referred to as CDT. Diminished mRNA concentration and glycoprotein glycosyltransferase activities involved in Tf N-glycan synthesis and increased sialidase activity most likely account for alcohol-induced increases in CDT. Knowledge about in vivo and in vitro effects on serum CDT is poor. Reliable CDT and non-CDT fractionation is needed for CDT measurement. Analysis methods with different analytical specificities and recoveries decreased the comparability of values and statistical parameters of the diagnostic efficiency of CDT. CDT is the most specific marker of chronic alcohol abuse to date. Efforts should concentrate on the pathomechanisms (in vivo), preanalysis, and standardization of CDT analysis.

Treatment settings for persons with alcoholism: evidence for matching clients to inpatient versus outpatient care

This study compared inpatient, intensive outpatient, and standard outpatient treatment settings for persons with alcoholism and tested a priori hypotheses about the interaction of setting with client alcohol involvement and social network support for drinking. Participants (N = 192) were assigned randomly in cohorts to 1 of the 3 settings. The settings did not differ in posttreatment primary drinking outcomes, although inpatients had significantly fewer jail and residential treatment days combined than outpatients. Clients high in alcohol involvement benefited more from inpatient than outpatient care; the opposite was true at low alcohol involvement levels. Network drinking support did not moderate setting effects. Clients low in cognitive functioning also appeared to benefit more from inpatient than outpatient care. Improved outcomes might be achieved by matching degree of alcohol involvement and cognitive functioning to level of care.

Carbohydrate-deficient transferrin as compared to other markers of alcoholism: a systematic review

This is a systematic review of the studies in which carbohydrate-deficient transferrin (CDT) has been compared to other laboratory markers in different experimental conditions, clinical settings, and populations. Only the studies (n = 54) in which CDT was compared either to the conventional or new biological markers of alcoholism, heavy drinking, or alcohol use were selected for further evaluation. Two prospective studies indicate that in men CDT is slightly more sensitive than gamma-GT in reflecting changes in these markers caused by drinking of a moderate and fixed amount of alcohol during three to four weeks. In one prospective study, in which the drinking history of male heavy drinking volunteers was as close the golden standard as possible; that is, obtained by a prospective anonymous drinking diary, CDT was slightly but not significantly better marker than conventional laboratory markers (ASAT, ALAT, gamma-GT and beta-Hex) in the identification of men drinking more than 400 g of alcohol daily. Similar prospective studies concerning women have not been done. Six prospective treatment outcome studies indicate that CDT may be a significantly more sensitive marker than gamma-glutamyltransferase (gamma-GT) in the detection of relapses in male alcoholics. However, these two tests can also be considered to be complementary markers. Furthermore, in the detection of relapses the baseline values of CDT and gamma-GT should be measured and compared on individual basis to the pretreatment values. Comparable data are not available from female alcoholics. In selective materials comprising male alcoholics and heavy drinkers, CDT was found to be a slightly more sensitive marker than gamma-GT in seven retrospective studies. In five studies, gamma-GT was slightly better. However, the differences between CDT and gamma-GT in general were not statistically significant. In three studies, the combined use of CDT and gamma-GT improved the sensitivity but with the expense of specificity. Only four studies included women and in three of these the sensitivity of gamma-GT was better than that of CDT, whereas in one study CDT was better than gamma-GT in the detection of female heavy drinkers. Seven studies performed in primary health care settings and among young populations demonstrate that the performance of CDT in the identification of heavy and problem drinkers in this type of populations is very low, although comparable to the poor performance of the conventional laboratory markers, too. According to seven studies, the sensitivity of gamma-GT is slightly better than that of CDT in the identification of excessive alcohol consumption among hospitalized male and female patients. However, in this type of hospital setting, the specificity of CDT is markedly higher than that of gamma-GT. There is some evidence indicating that the performance of the tests can be improved with the combined use of both tests. Eight studies indicate that both in men and women CDT is a better marker than gamma-GT in the identification of alcohol abuse among patients with alcoholic and nonalcoholic liver diseases. This is mostly due to the higher specificity of CDT as compared to that of gamma-GT.

Limitations of CDT and GGT in detecting relapses in patients attending an alcohol problems clinic

Biochemical markers of alcohol consumption are useful for the detection and monitoring of problem drinking. Blood samples from 37 patients attending an alcohol treatment clinic were analysed for GGT and %CDT, and results were compared with self-reported periods of abstinence and alcohol consumption. Poor correlation was obtained between GGT and %CDT, and between these assays and self-reported alcohol use. The apparent sensitivity and specificity of GGT (57%, 63%) and %CDT (43%, 88%), were considerably lower than those reported by other workers.

Utility of liver function tests for screening "alcohol abusers" who are not severely dependent on alcohol

This study evaluated the utility of using liver function tests to identify low dependence outpatient "alcohol abusers" (N = 253) and for evaluating changes in their drinking over the course of treatment. Despite drinking at levels considered to pose a health risk (i.e., drinking on 72% of all days in the year prior to treatment and averaging 6.3 drinks per drinking day), nearly two-thirds had normal liver function tests at treatment entry. It is concluded that for problem drinkers the cost of using liver function tests outweighs the benefits.

Biological markers as indicators for relapse in alcohol-dependent patients

Although biological markers such as carbohydrate-deficient transferrin (CDT), γ-glutamyl transferase (GGT) and mean corpuscular volume (MCV) have been used as indicators for heavy alcohol consumption and alcoholism little information is available on the utitlity of these markers in detecting relapses. In this study the value of the biological markers CDT, GGT and MCV was examined in monitoring an outpatient treatment programme for alcohol-dependent patients. In 163 male alcoholic patients CDT, GGT and mean corpuscular volume (MCV) were assayed at the beginning and after 6 months during the outpatient programme. All markers distingushed between relapsers and abstainers (p<0.01). The sensitivity for relapses was 55% for CDT, 50% for GGT and 20% for MCV. Combining all markers the sensitivity could be enhanced to 85%, with only a little loss of specificity (85%). The highest positive predictive value was 73% for CDT used as a single marker. The negative predictive value (CDT 93%, GGT 92%, MCV 88%) and the diagnostic efficiency (CDT 91%, GGT 87%, MCV 85%) of all markers were very high. These results indicate that CDT is the most efficient marker for alcohol relapses, followed by GGT. MCV seems to be a marker of second choice.