Detection of relapses in alcohol-dependent patients using carbohydrate-deficient transferrin: improvement with individualized reference levels during long-term monitoring

Alcohol biomarkers as tools to guide and support decisions about intoxicated driver risk

OBJECTIVES

This article describes the results of a pilot study that used alcohol biomarkers to guide decisions about driving under the influence (DUI) driver risk in the United States, replicating a European best practices model. The pilot tested whether biomarkers (1) can help the assessor identify high-risk drivers who continue to drink heavily after their arrest and (2) detect relapses in drivers enrolled in their drivers' safety plans.

METHODS

These questions were addressed using two biomarkers, carbohydrate-deficient transferrin (CDT), and the Early Detection of Alcohol Consumption (EDAC) test, to evaluate the drinking behavior in repeat offenders during the assessment interview (baseline) and at 3, 6, 9, and 12 months' follow-up. The cutoff used to determine heavy drinking at baseline was 2.2 percent CDT and 40 percent P-positive for EDAC. A 30 percentage point increase in biomarker value from an abstinent baseline signaled a relapse and a 30 percentage point decrease in biomarker value from a previous positive measure signaled reduced drinking/abstinence.

RESULTS

The results show that the EDAC used alone identified 18 percent of drivers as heavy drinkers at baseline compared to 5 percent for CDT and 8 percent for GGT. The best detection rate was achieved with the EDAC-CDT combination, which captured heavy drinking in 20 percent of the repeat offenders at baseline, most of whom (68%) denied drinking at the assessment interview. During follow-up, 52 percent of drivers abstained/reduced their drinking, almost 20 percent experienced a relapse, and 30 percent remained noncompliant with testing. Drivers who relapsed were less likely to be employed full-time (67 versus 84%) or married (17 versus 30%) compared to those who abstained. Of the drivers who relapsed, 80 percent returned to abstinence or reduced their drinking after biomarker information was used as brief intervention by the counselors.

CONCLUSION

Biomarker testing improved the assessment and monitoring of repeat offenders in this pilot because it provided an objective tool to identify high-risk drivers allowing for better treatment recommendations and helped identified drivers who relapsed during follow-up to facilitate a brief intervention by the counselor that resulted in reduced alcohol consumption. These results contribute to establish evidence based practices in highway safety and are setting up new guidelines in the United States to reduce drunk driving.

Using the EDAC™ Test to Monitor Abstinence and Relapses During Outpatient Treatment

The main objective of this study is to show the performance of the EDAC test in monitoring alcohol consumption during outpatient treatment. The EDAC is a new approach that uses routine laboratory tests to identify binge drinking as well as chronic drinking. The overall diagnostic performance of the EDAC fluctuates around 80 to 90% for both specificity and sensitivity. Close to two thousand subjects have been tested by the EDAC since the early eighties; 300 of these were patients undergoing treatment at different institutions across the U.S. This article selected five case studies to represent examples of classical drinking behaviors encountered in most outpatient clinics. The first four cases illustrate the use of the EDAC alone and the last case represents the use of the EDAC combined with CDT. These five case studies illustrate the use of the EDAC to detect relapse episodes, to monitor abstinence during outpatient treatment and to recognize a slip early enough to prevent more severe drinking. The use of biomarkers to monitor drinking behavior in alcohol dependent patients is gaining popularity because they provide objective information on a patient's drinking status when used as an adjunct to self-report.

Factors Affecting %CDT Status at Entry Into a Multisite Clinical Treatment Trial: Experience from the COMBINE Study

BACKGROUND

Carbohydrate-deficient transferrin (CDT) occurs as a higher percentage of normal transferrin (%CDT) in heavy drinkers. %CDT is used as a marker of both alcohol use disorder severity and treatment outcome both clinically and in treatment trials. Nevertheless, little is known about the parameters that predict which patients are %CDT positives at treatment entry. These parameters might include level of drinking, days of abstinence before testing, and severity of alcohol dependence before evaluation.

METHODS

%CDT levels were collected before randomization from participants of the COMBINE Study, a large federally sponsored multisite clinical trial evaluating medications and behavioral therapies in alcohol-dependent outpatients. %CDT (assayed in a central laboratory) was available in 1,193 individuals for whom drinking history in the 30 days before testing and measures of alcoholism severity were documented. The effects of drinking history and alcohol severity were evaluated for prediction of a %CDT-positive test status.

RESULTS

Less percent days abstinent (PDA) and more drinks per drinking day (DDD) were predictive of higher rates of %CDT-positive patients (maximum 67%). Up to 14 days of continuous abstinence before testing did not appear to significantly affect %CDT status. Rates of %CDT positives remained reasonably steady up to about 40% PDA. Years of drinking at dependence levels had an unexpected negative impact on %CDT-positive rates while previous treatment had a small but positive impact of %CDT-positive rates. ADS and DrInC scores had no predictive value over and above recent drinking amounts on %CDT status.

CONCLUSIONS

%CDT is more likely to be positive in those who have more days of drinking and to a lesser degree in those who drink more per drinking day. It can remain positive even in those alcoholic subjects who stop drinking many days before testing. Alcoholic subjects with more treatment experiences appear to have a marginally higher %CDT-positive rate.

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.

The Effectiveness of Anxiety Treatment on Alcohol-Dependent Patients with a Comorbid Phobic Disorder: A Randomized Controlled Trial

OBJECTIVE

Evidence has emerged which indicates that the post-treatment relapse rate for alcohol-dependent patients with a comorbid anxiety disorder is higher than for alcohol-dependent patients without a comorbid anxiety disorder. The question raised by this evidence is whether the relapse rate in these dually diagnosed patients could be reduced if they were given additional treatment for the comorbid anxiety disorder. We attempted to answer this question by conducting a trial among patients with a double diagnosis of alcohol dependence and agoraphobia or social phobia.

METHOD

We conducted a 32-week randomized controlled trial among 96 abstinent patients with a primary diagnosis of alcohol dependence and a comorbid anxiety disorder involving agoraphobia or social phobia. The patients were randomly assigned to an intensive psychosocial relapse-prevention program on its own (n = 49) or in combination with an anxiety treatment program comprising cognitive behavioral therapy (CBT) and optional pharmacotherapy consisting of an SSRI (n = 47). The primary outcome measure was the percentage of patients who suffered an alcohol relapse during a 32-week period. The secondary outcome measures were total abstinence, a reduction in the days of heavy drinking, and less severe anxiety symptoms.

RESULTS

Although the additional therapy clearly reduced the anxiety symptoms, it had no significant effect on the alcohol relapse rates.

CONCLUSION

Anxiety treatment for alcohol-dependent patients with a comorbid anxiety disorder can alleviate anxiety symptoms, but it has no significant effect on the outcome of alcohol treatment programs.

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.

A review of genetic, biological, pharmacological, and clinical factors that affect carbohydrate-deficient transferrin levels

BACKGROUND

Carbohydrate-deficient transferrin (CDT) is an alcohol biomarker recently approved by the U.S. Food and Drug Administration. This test is increasingly being used to detect and monitor alcohol use in a variety of health care, legal, and industrial settings. The goal of this study is to review the genetic, biological, pharmacological, and clinical factors that may affect CDT levels.

METHODS

A review of the literature identified 95 research articles that met the authors' criteria and reported potential interactions of a variety of factors on percent and total CDT levels. The review established 12 categories of variables that may affect CDT levels. These categories include (1) alcohol use, (2) genetic factors, (3) race, (4) gender, (5) age, (6) liver disease, (7) iron levels, (8) tobacco use, (9) medication such as estrogen and anticonvulsants, (10) metabolic factors such as body mass index and total body water, (11) chronic medical conditions such as rheumatoid arthritis, and (12) surgical patients.

RESULTS

There is evidence that %CDT levels are affected by alcohol use, end-stage liver disease, and genetic variants. In addition to these three factors, total CDT levels (CDTect) are also affected by factors that raise transferrin levels such as iron deficiency, chronic illnesses, and menopausal status. Other potential factors such as tobacco and age appear to be confounded by alcohol use. The roles of female gender, low body mass index, chronic inflammatory diseases, and medication on CDT levels require further study. False negatives are associated with female gender, episodic lower level alcohol use, and acute trauma with blood loss.

CONCLUSIONS

This review suggests that a number of factors are associated with false-positive CDTect and %CDT levels. CDT offers great promise to assist physicians in the care of patients to detect and monitor heavy alcohol use.

Biological markers in alcoholism

Alcohol biomarkers include tests indicative of acute or chronic alcohol consumption (state markers), and markers of a genetic predisposition to develop alcohol dependence after chronic exposure (trait markers). While a comprehensive trait marker for alcohol dependence has not been identified, a number of successful state markers for monitoring drinking status are used clinically. These tests provide direct or indirect ways to estimate the amounts of alcohol consumed and the duration of ingestion, and to detect any harmful effects on body functions resulting from long-term misuse. The most obvious method to prove recent drinking is by demonstrating the presence of ethanol in body fluids or breath, but, because ethanol is cleared fairly rapidly from the body, this method is limited to detect only very recent drinking. Measurement of urinary 5-hydroxytryptophol or ethyl glucuronide provide more sensitive methods to disclose recent drinking, because their washout constants are much longer than for ethanol. The liver functions test (GGT, AST and ALT in serum) and the mean corpuscular volume of erythrocytes (MCV) are among the standard diagnostic tools used to identify chronic alcohol exposure. The main disadvantage with these measures is that they have low sensitivity for recent excessive intake, and that raised levels may result from several causes besides heavy drinking, implying a low specificity for alcohol. Carbohydrate-deficient transferrin (CDT), which refers to changes in the carbohydrate composition of serum transferrin, is a more specific marker for identifying excessive alcohol consumption and monitoring abstinence during outpatient treatment. The alcohol biomarkers improves knowledge of drinking patterns in both individuals and populations, and they are also valuable tools for the objective evaluation of treatment efforts. Alcohol markers have, for example, found uses in early identification of at-risk and harmful drinking, and they help to monitor abstinence and relapse in response to outpatient treatment.

5-hydroxytryptophol as a marker for recent alcohol intake

AIMS

To review the mechanism behind the alcohol-induced shift in serotonin metabolism, and the use of urinary 5-hydroxytryptophol (5-HTOL) as a biochemical marker of acute alcohol consumption.

BACKGROUND

The serotonin metabolite 5-HTOL is a normal, minor constituent of urine and is excreted mainly in conjugated form with glucuronic acid. The formation of 5-HTOL increases dramatically after alcohol intake, due to a metabolic interaction, and the elevated urinary excretion remains for some time (>5-15 hours depending on dose) after ethanol has been eliminated. This biochemical effect can be used for detection of recent alcohol intake.

RESULTS

5-HTOL is determined by the gas chromatography-mass spectrometry (GC-MS) or liquid chromatography and mass spectrometry (LC-MS) techniques. A new ELISA method for 5-HTOL glucuronide provides a promising clinical assay. The most robust way to use the marker is by measuring the ratio of 5-HTOL to 5-hydroxyindoleacetic acid, because this compensates for urine dilution and dietary intake of serotonin. 5-HTOL is a very sensitive and specific indicator of recent alcohol consumption and, as such, a valuable complement to self-report. In clinical use, 5-HTOL is effective for monitoring lapses into drinking during out-patient treatment and for objective evaluation of treatment efforts. Other applications include detection of high-risk patients in elective surgery, monitoring of disulfiram treatment and a method to rule out artefactual ethanol formation in forensic toxicology. 5-HTOL can also be used as a sensitive reference method for validation of self-report data in clinical alcohol research.

CONCLUSIONS

An elevated urinary 5-HTOL level can serve as a sensitive and reliable marker for recent alcohol intake with a number of clinical and forensic applications.

A 6-month controlled naltrexone study: combined effect with cognitive behavioral therapy in outpatient treatment of alcohol dependence

BACKGROUND

In several studies, patients with alcohol dependence treated with the opioid antagonist naltrexone have shown fewer relapses to heavy drinking than those receiving placebo. An interaction between the naltrexone effect and the type of psychological therapy has been observed.

METHODS

A 6-month, double-blind, placebo-controlled, parallel-group study was performed at 10 different investigation sites. After a placebo run-in period of 1 week, 118 patients were randomized into 4 treatment groups-50 mg of naltrexone daily or placebo in combination with either cognitive behavioral therapy (CBT) or supportive therapy. The CBT was performed over nine sessions according to the manual of Project MATCH (Matching Alcoholism Treatments to Client Heterogeneity). The supportive therapy was defined as "the treatment as usual." Alcohol consumption, craving, carbohydrate-deficient transferrin, medication compliance by tablet count, and adverse clinical events were assessed at all visits. Other liver enzymes and psychiatric symptoms were also determined.

RESULTS

Ninety-one (77%) patients completed the study, and 92 (78%) were 80% compliant with the medication regimen. A lower percentage of heavy-drinking days was shown in the naltrexone group (p = 0.045) compared with the placebo group, as was a lower craving score (p = 0.029). These results are supported by the lower levels of liver enzyme activities (p < 0.010 for aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase), but not by the carbohydrate-deficient transferrin levels, in the naltrexone group. The mean time period before the first day of heavy drinking was longer for the group treated with CBT (p = 0.010), especially in combination with naltrexone (p = 0.007). Naltrexone was well tolerated, and no patients discontinued the study due to side effects.

CONCLUSIONS

This study supports the effect of naltrexone in outpatient treatment of alcohol dependence and suggests that a beneficial interaction effect with CBT can be expected.

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.

[Peripheral markers, future perspectives]

Four of the recently described peripheral markers of alcohol abuse have been reviewed. The acetaldehyde adducts allow to detect an alcohol abuse lasting for several weeks, even after a recent alcohol withdrawal. Inversely, 5-hydroxytryptophol (5-HTOL) reflects the alcohol consumption of the last 24 hours. Its detection is possible after the blood alcohol concentration has disappeared. Its measurement is run in urine samples, thus without invasive sampling. The hyaluronic acid and the activity of beta-hexosaminidase are markers of hepatobiliary alcohol induced disorders more than direct markers of alcohol intake. Acetaldehyde adducts could be used as markers of long term alcohol abuse, CDT as a marker of the recent alcohol abuse, and 5-HTOL the detection of alcohol abuse of the past day.

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.

Should We Use Carbohydrate-deficient Transferrin instead of γ-Glutamyltransferase for Detecting Problem Drinkers? A Systematic Review and Metaanalysis

Background: Carbohydrate-deficient transferrin (CDT) has been used as a test for excessive alcohol consumption in research, clinical, and medico-legal settings, but there remain conflicting data on its accuracy, with sensitivities ranging from &lt;20% to 100%. We examined evidence of its benefit over a conventional and less expensive test, γ-glutamyltransferase (GGT), and compared the accuracy of different CDT assay methods.

Methods: We performed a systematic review using summary ROC analysis of 110 studies prior to June 1998 on the use of CDT in the detection of alcohol dependence or hazardous/harmful alcohol use.

Results: We identified several potential sources of bias in studies. In studies examining CDT and GGT in the same subjects, subject characteristics were less likely to influence the comparison. In such paired studies, the original Pharmacia CDT assay was significantly more accurate than GGT, but the modified CDTect assay did not perform as well as the original and was not significantly better than GGT. The accuracy of the AXIS %CDT assay was statistically indistinguishable from modified CDTect. Several CDT assay methods appeared promising, in particular, liquid chromatography (chromatofocusing, HPLC, fast protein liquid chromatography) and isoelectric focusing, but there were insufficient paired studies from which to draw firm conclusions.

Conclusions: In studies published before June 1998, the results obtained with commercially available CDT assays were not significantly better than GGT as markers of excessive alcohol use in paired studies. Further high-quality studies comparing CDTect (modified) and other CDT assays with GGT in the same subjects are needed.

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.

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.

Carbohydrate-deficient transferrin in the assessment of harmful alcohol consumption: diagnostic performance and clinical significance

The last decade saw the emergence of carbohydrate-deficient transferrin (CDT) as the most promising marker for the diagnosis of alcohol abuse. Daily alcohol consumption of four beers, four glasses of wine or three standard drinks causes increased concentrations of CDT in serum. CDT is serum transferrin with a reduced content of oligosaccharides due to the detrimental effects of alcohol metabolism on the glycosylation pathway of hepatocytes and/or the increased activity of circulating glycosidases in serum. Most current CDT procedures entail separation of normal transferrin from CDT in a charged matrix-like isoelectric focusing and ion exchange chromatography, followed by detection/quantitation of CDT by a myriad of immunoassays: immunoblotting, radioimmunoassay, enzyme immunoassay and nephelometry. New CDT procedures present the advantages of improved performance, inexpensive automation and CDT results expressed as a percentage of total serum transferrin. CDT's major asset is its high specificity in well-defined populations i.e. individuals ingesting 60 g alcohol daily for at least a week.The sensitivity rates, which vary between 22% and 81%, depend on the amount of alcohol ingested, time of sample collection after the cessation of drinking, age, gender and the cut-off point chosen for analysis of tests' results. Regarding clinical applications, best outcome is achieved when the test is used to confirm a suspicion of alcohol abuse and when monitoring abstinence and relapses.The low prevalence of alcohol abuse in the general population challenges its use as a screening test.With the advent of inexpensive automation and the constant emergence of innovative, improved tests, we are seeing the rise of a new era in alcohol abuse diagnosis as affordability and education allows widespread use of CDT in a variety of settings.

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.

The effect of drinking intensity and frequency on serum carbohydrate-deficient transferrin and gamma-glutamyl transferase levels in outpatient alcoholics

Whereas heavy alcohol consumption is known to elevate serum carbohydrate-deficient transferrin (CDT) and gamma-glutamyl transferase (GGT) levels, the contribution of drinking pattern to these effects is not completely understood. We present data on 423 men and 146 women evaluated 1 year after treatment in a large-scale alcoholism treatment study (Project MATCH). Relationships between drinking frequency (number of days drinking), intensity (drinks per drinking day), and blood levels of CDT and GGT were analyzed by using response surface regression models and thin-plate spline-smoothing techniques. Both models indicated differences between CDT- and GGT-drinking pattern relationships in men and, also, a difference between men and women in CDT drinking-pattern relationships. For men, CDT levels appeared to respond primarily to frequency of drinking, whereas GGT was influenced primarily by drinking intensity. For women, both CDT and GGT were influenced more by drinks per drinking day (intensity) than by number of days drinking (frequency). The data confirm both the independent nature of these biological markers of alcohol consumption and gender differences in alcohol-induced CDT response reported previously.

Intra- and interindividual variability of carbohydrate-deficient transferrin, γ-glutamyltransferase, and mean corpuscular volume in teetotalers

Blood samples for determination of the biochemical alcohol markers carbohydrate-deficient transferrin (CDT) in serum, γ-glutamyltransferase (GGT) in serum, and erythrocyte mean corpuscular volume (MCV) were collected once every 1–2 weeks over ∼5 months from 10 female and 4 male teetotalers. Mean values for serum CDT (using the CDTectTM assay) ranged from 9.9 to 29.4 units/L (median, 14.2 units/L), and the highest results were obtained in the women. The mean values for serum GGT ranged from 0.15 to 0.49 μkat/L (median, 0.30 μkat/L, or 18 U/L) except for one woman with a very high mean of 3.07 μkat/L. For MCV, the mean values ranged from 79.5 to 91.5 fL. Two women showed several CDT results above the upper reference limit (mean values, 27.6 and 29.4 units/L, respectively); however, their GGT and MCV values fell within the reference intervals. One of these women exhibited an increased total transferrin concentration (mean value, 5.38 g/L), which was possibly related to the use of oral contraceptives and/or a low serum iron concentration. When the CDTect value was expressed relative to total transferrin, a ratio within the reference interval was observed for this woman but not for the other woman with increased CDTect values. The present study demonstrates a considerable variation between individuals in CDT, GGT, and MCV without drinking any alcohol. The results also show that these baseline values are fairly constant over time within the same individual.

Usefulness of carbohydrate-deficient transferrin in alcoholic patients with normal gamma-glutamyltranspeptidase

The biological diagnosis of alcoholism is conducted routinely by assay of gamma-glutamyltranspeptidase (GGT) and mean corpuscular volume (MCV). However, their low specificity and sensitivity have prompted research to find other more reliable parameters. Stibler showed an increase in desialylated transferrin [carbohydrate-deficient transferrin (CDT)] in alcoholic patients. The normal value of the serum CDT concentration is under 60 mg/liter; a value between 60 and 100 mg/liter indicates probable alcoholism, and a value > 100 mg/liter indicates a very high probability of alcoholism (specificity: 99%). Its sensitivity ranges from 60 to 91%, and its specificity ranges from 92 to 100%. Its half-life is 17 +/- 4 days. CDT is thus a useful laboratory marker, but its assay is costlier and more complex than that of GGT. This study concerns 31 alcohol-dependent patients as defined by DSM-IV, with GGT levels in the normal range. It evaluates CDT at day 0 and its time course after 15 days withdrawal. GGT and MCV were assayed concomitantly. Remarkably, the results show a sensitivity of 83.9 (26 positives of 31) in this particular population and a specificity of 92.2. The fall in CDT after 15 days withdrawal was 36%. CDT is thus a particularly useful marker for the diagnosis and follow-up of alcoholics with normal GGT levels.

Validation by isoelectric focusing of the anion-exchange isotransferrin fractionation step involved in determination of carbohydrate-deficient transferrin by the CDTect assay

Serum concentration of carbohydrate-deficient transferrin (CDT) is used for laboratory diagnosis of chronic alcohol abuse. Using isoelectric focusing for validation of the initial isotransferrin fractionation step involved in the determination of CDT by the CDTect assay, we found a complete in vitro iron saturation of transferrin and sufficient stability of the transferrin iron load during column passage; effective separation of non-CDT-isotransferrins and CDT-isotransferrins at the microcolumns; partial coelution of trisialo-Fe2-transferrin, which did not significantly affect CDT measurement; partial retention of CDT-isotransferrins, especially disialo-Fe2-transferrin, which may cause falsely negative results for CDT at the upper reference limits; good precision of the isotransferrin fractionation step; and no significant effects of low concentrations of serum protein and transferrin. We strongly urge standardization of CDT analysis and suggest isoelectric focusing for validation of CDT analysis methods and verification of odd results.

Carbohydrate deficient transferrin in detecting relapse in alcohol dependence

Patients reports together with findings at clinical examination and information from an informant such as a relative were used to categorise patients as relapsed or not relapsed during a 6 month period of out-patient treatment at an alcohol problems clinic. At each fortnightly visit, blood was taken for measurement of serum gamma-glutamyl transferase and carbohydrate deficient transferrin (Pharmacia method). A total of 53 patients attended for at least one follow-up visit. Mean CDT differentiated relapsers from non-relapsers at seven of the 11 visits (P < 0.05), but at no visit did mean GGT differentiate. CDT tended to become elevated after a relapse more quickly than GGT. However, whether using upper limit of normal (ULN), or defining a 'positive test' as > last test and either > 20% above lowest previous test or > ULN, specificity (averaged over the 11 visits) was greater for GGT than CDT. Some of the false positive results for CDT were in patients who, shortly after having a positive test, relapsed, suggesting that a rising CDT can herald a relapse admitted by the patient. This could not be shown for false positive GGT results. Inspection of individual trajectories of alcohol consumption and blood test results shows that for some patients GGT is the more effective marker of relapse, whilst for others CDT operates better.

Carbohydrate-deficient transferrin and gamma-glutamyl transferase levels during disulfiram therapy

Serum samples for quantification of carbohydrate-deficient transferrin (CDT) and gamma-glutamyl transferase (GGT) were collected from alcohol-dependent men and women upon admission to the hospital for detoxification, and repeatedly over a 3- to 5-week period of supervised disulfiram administration as outpatients. On admission, 10 of 12 patients showed CDT concentrations above the conventional cutoff limits, whereas 6 had elevated GGT values. Normalization usually occurred within 1 to 3 weeks of disulfiram treatment, after which CDT and GGT leveled out at a relatively stable individual baseline level. However, in those patients with the highest values on admission, the decline continued during the entire observation period. The time for normalization of GGT was typically longer than for CDT. In four male patients who had taken disulfiram regularly (400-800 mg every second or third day) for at least 3 months before entering the study, the CDT and GGT concentrations were stable over time and all fell within normal limits. The present results indicate that disulfiram treatment does not influence the serum level of CDT. It is also suggested that consecutive CDT and GGT measurements during outpatient treatment with disulfiram after detoxification can be used to identify the individual baseline (i.e., abstinence) values for CDT and GGT, and, furthermore, for monitoring treatment outcome.

Carbohydrate-deficient transferrin as an indicator of drinking status during a treatment outcome study

Biological markers of alcohol consumption have been used in both clinical and research settings to aid in the identification of relapse drinking. Although carbohydrate-deficient transferrin (CDT) has been shown to be a sensitive and specific marker for the identification of heavy drinkers, little data are available as to its utility as a marker for relapse drinking during treatment, particularly in comparison with the more widely used serum gamma-glutamyltransferase (GGT). CDT and GGT were measured in 35 male alcoholics before entering, and every 4 weeks during, a 12-week outpatient treatment trial combining pharmacotherapy and cognitive behavioral therapy. CDT and GGT were again measured 14 weeks after completion of treatment. During the 12-week treatment period, CDT showed a significant difference in those individuals who abstained from drinking (30% decrease), compared with those who relapsed (10% increase). GGT decreased on average in all individuals, and the change from treatment entry did not differ significantly across the drinking outcome groups. The change in CDT, but not GGT, from study entry to termination, significantly correlated with total alcohol consumption during the trial. At the 14-week posttreatment, follow-up evaluation CDT showed about a 60% elevation and GGT showed a 30% elevation, on average, from study entry values in those individuals who had relapse drinking by self and/or collateral report. The change in both markers differed between those individuals who remained abstinent or relapsed during the poststudy period. In general, the change in CDT from pretreatment levels seemed more sensitive to drinking status during treatment and follow-up than GGT. This indicates that CDT may be more sensitive marker for evaluating drinking status during both clinical and research treatment trials.