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

Low-pressure chromatographic separation and UV/Vis spectrophotometric characterization of the native and desialylated human apo-transferrin

Low-pressure pH gradient ion exchange separation provides a fast, simple and cost-effective method for preparative purification of native and desialylated apo-transferrin. The method enables easy monitoring of the extent of the desialylation reaction and also the efficient separation and purification of protein fractions after desialylation. The N-glycan analysis shows that the modified desialylation protocol successfully reduces the content of the sialylated fractions relative to the native apo-transferrin. In the optimized protocol, the desialylation capacity is increased by 150 %, compared to the original protocol provided by the manufacturer. The molar absorption coefficients in the near-UV region for the native and desialylated apo-transferrin differ by several percent, suggesting a subtle dependence of the glycoprotein absorbance on the variable sialic acid content. The method can easily be modified for other glycoproteins and is particularly appropriate for quick testing of sialic acid content in the protein glycosylation patterns prior to further verification by mass spectrometry.

Carbohydrate deficient transferrin (CDT) predicts heavy drinking in adolescents with alcohol dependence

A biomarker that could indicate problematic drinking in adolescents and/or reflect changes in heavy drinking would be a valuable addition to prevention, treatment, and research efforts. Carbohydrate deficient transferrin (CDT) is a valid biomarker of heavy drinking in adults; however, it is not well examined in adolescents. Adolescents with alcohol dependence (AD) (n = 21; 9 females) and non-dependent controls (ND) (n = 6; 3 females), ages 14-20, were interviewed to determine drinks per drinking day, peak number of drinks, and percent days heavy drinking (≥4 standard drinks/day). Blood samples from participants were assayed for percent of transferrin that was carbohydrate deficient (%CDT). Analyses compared groups on drinking and %CDT, examined the relationship between %CDT and indices of drinking, and provided preliminary estimates of the test validity of %CDT for heavy drinking in adolescents. Among adolescents with AD, %CDT was significantly and strongly correlated (r = .54) with percent heavy drinking days, and this relationship was consistent for both males and females. AD adolescents did not differ from ND on mean %CDT levels, despite significantly greater alcohol use. Indicators of test validity showed that %CDT had low sensitivity (33%) but adequate specificity (83%) for heavy drinking. Results provide proof of concept that %CDT is a potentially valuable tool to use in alcohol treatment and research in adolescents. Even if %CDT does not discriminate between adolescents with and without alcohol dependence, it could be an effective monitoring tool to indicate changes over time in binge drinking. Improved %CDT measurement methods might enhance its utility.

Socioeconomic status and trends in alcohol drinking in the Danish MONICA population, 1982- 92

Aims: To examine trends in alcohol drinking in different educational groups.

Methods: Data from three cross-sectional WHO MONICA surveys conducted in 1982-84, 1987, and 1991-92 were analysed to estimate trends in abstention, moderate, heavy, and sporadic heavy alcohol use in relation to level of education, age and smoking. In total, 6,695 Danish men and women aged 30, 40, 50, and 60 years were included.

Results: Alcohol drinking decreased in both men and women during the study period, but changes were only significant among the highest educated. In the highest educated men the prevalence of moderate alcohol use increased from 77 to 82%, while heavy alcohol use declined from 19 to 12%. In the highest educated women the prevalence of abstention increased from 15 to 22%, while moderate alcohol use declined from 78 to 68%.

Conclusion: During the 1980s, alcohol drinking decreased among the highest educated men and women and an educational gradient in alcohol drinking widened in men and attenuated in women.

Immune response to acetaldehyde-human serum albumin adduct among healthy subjects related to alcohol intake

Acetaldehyde (AA) is the main metabolic product in ethanol metabolism, although it can also derive from sources of airborne pollution. As a typical aldehyde, AA is able to react with a variety of molecular targets, including DNA and protein. This property justifies the hypothesis of a immune reaction against this kind of adduct, to be studied by a seroprevalence screening approach. In this study, the correlation between drinking habits and the amount of circulating AA-human serum albumin adduct (AA-HSA) was evaluated in a group of healthy subjects, non alcohol-addicted. Daily ethanol intake (grams) was inferred for each subject using the information collected through a questionnaire, and AA-HSA antibodies (AA-HSA ab) analyses were performed using the Displacement Assay on whole blood samples. The findings showed a correlation between ethanol intake and immune response to molecular adduct. These results underscore the evaluation of AA-HSA ab amount as a suitable molecular marker for alcohol intake that can be applied in future investigations on a large scale for prevention screening.

Pregnancy and variations of carbohydrate-deficient transferrin levels measured by the candidate reference HPLC method

AIMS

Contrasting data are available on the diagnostic accuracy of carbohydrate-deficient transferrin (CDT) during pregnancy. These differences may depend in part on how CDT was evaluated and expressed. Here, we report on variations of CDT levels in pregnant women using the high performance liquid chromatography (HPLC) candidate reference method.

METHODS

Alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, mean corpuscular volume, serum transferrin, urine and serum ethyl glucuronide and CDT were measured in 64 women, self-reporting as non-alcohol abusers (age: median 34, IQR: 28-38), at different stages of normal pregnancy (gestational weeks: median 28, IQR: 8-33). CDT was expressed as percentage of disialotransferrin to total transferrin (%CDT).

RESULTS

Transferrin was associated with both %CDT (r = 0.66; P < 0.001) and gestational week (r = 0.68; P < 0.001). Interestingly, %CDT was highly correlated with gestational week (r = 0.77; P < 0.001), even after controlling for the effect of transferrin. Moreover, statistically significant differences in %CDT were also evident between women grouped for pregnancy trimester (first trimester: mean 1.01% (SD 0.19); second trimester: 1.30% (SD 0.14); third trimester: 1.53% (SD 0.22); ANOVA P < 0.001). Trend analysis confirmed a proportional increase of %CDT along with pregnancy trimesters (P < 0.001).

CONCLUSIONS

%CDT, measured with the HPLC candidate reference method, is independently associated with gestational week. Differently from what has been previously reported or expected, the relationship between pregnancy and CDT could be more complex. The diagnostic accuracy of CDT for detecting alcohol abuse in a legal context may be limited in pregnant women and the effect of gestational age should be considered.

A critical review of methods for characterisation of polyphenolic compounds in fruits and vegetables

Phenolic compounds, ubiquitous in plants, are of considerable interest and have received more and more attention in recent years due to their bioactive functions. Polyphenols are amongst the most desirable phytochemicals due to their antioxidant activity. These components are known as secondary plant metabolites and possess also antimicrobial, antiviral and anti-inflammatory properties along with their high antioxidant capacity. Many efforts have been made to provide a highly sensitive and selective analytical method for the determination and characterisation of polyphenols. The aim of this paper is to provide information on the most recent developments in the chemical investigation of polyphenols emphasising the extraction, separation and analysis of these compounds by chromatographic and spectral techniques.

Natural antioxidants: fascinating or mythical biomolecules?

Research on the use, properties, characteristics and sources of antioxidants especially phenolic compounds, flavonoids, vitamins, synthetic chemicals and some micronutrients began in the late 18^th century. Since then antioxidant research has received considerable attention and over a hundred thousand papers have been published on the subject. This has led to a rampant use of antioxidants in order to try to obtain and preserve optimal health. A number of nutraceuticals and food supplements are frequently fortified with synthetic or natural antioxidants. However, some research outcomes have led to the belief that antioxidants exist as mythical biomolecules. This review provides a critical evaluation of some common in vitro antioxidant capacity methods, and a discussion on the role and controversies surrounding non-enzymatic biomolecules, in particular phenolic compounds and non-phenolic compounds, in oxidative processes in an attempt of stemming the tidal wave that is threatening to swamp the concept of natural antioxidants.

Validation of a self‐administered modified CAGE test (CAGE‐C) in a somatic hospital ward: Comparison with biochemical markers

OBJECTIVE

The time frame for the original CAGE questionnaire is lifetime and it does not quantify drinking frequency and may be less suitable in a population with very few teetotalers. The purpose of this study was to validate a variant of the CAGE questionnaire and compare it with the outcome of a thorough interview according to DSM-III and ICD-10 criteria and to the outcome of biochemical markers in inpatients in a somatic hospital setting.

MATERIAL AND METHODS

The questionnaire and biochemical markers were tested on a random sample of 130 patients admitted to a department of orthopedic surgery. The result of a diagnostic interview with a trained staff member from the local alcohol treatment unit was used as the gold standard. Data were analyzed by means of receiver operating characteristic (ROC) curves.

RESULTS

In this population 25 % had an alcohol problem and the questionnaire proved to be valid, with a sensitivity and specificity of 0.94 and 0.88, respectively, while the positive predictive value (PVpos) was 0.73 and the negative predictive value (PVneg) was 0.98. Carbohydrate-deficient transferrin (CDT) had a sensitivity and a specificity of 0.47 and 0.96, and PVpos and PVneg of 0.80 and 0.85, respectively.

CONCLUSIONS

This new diagnostic questionnaire is simple, easy to administer and suitable for screening purposes in populations with a high prevalence of at-risk drinkers.

Enzyme linked lectin assay (ELLA) for direct analysis of transferrin sialylation in serum samples

OBJECTIVES

Glycosylation analysis provides many opportunities for diagnostics, but its complexity hampers its routine application. Aiming to alleviate this problem, we developed a simple assay that can measure sialylation of transferrin directly from serum.

DESIGN AND METHODS

Transferrin samples with different levels of sialylation were prepared by desialylation. Enzyme-linked-lectin assay (ELLA) and high-performance anion-exchange chromatography (HPAEC) have been used to analyze transferrin sialylation. Periodate oxidation was used to oxidize carbohydrates on antibodies.

RESULTS

ELLA was developed for the analysis of serum transferrin sialylation. Antibodies oxidized in situ with periodate have been used to capture transferrin from serum samples. Sialic acid on transferrin has been detected with Sambucus nigra agglutinin (SNA) lectin. Transferrin samples with different sialylation levels prepared by differential desialylation have been used as standards. Accuracy of the method has been confirmed by comparison to HPAEC analysis.

CONCLUSIONS

A rapid and simple ELLA that can be routinely used for the analysis of serum transferrin sialylation has been developed.

A randomized controlled trial of Minnesota day clinic treatment of alcoholics

AIM

To compare the Minnesota day clinic treatment with the traditional public psychosocial treatment.

DESIGN

Randomized controlled trial.

SETTING

Public out-patient alcohol clinic and privately funded Minnesota day clinic in Denmark.

PARTICIPANTS

A total of 148 individuals with alcohol dependence were included in a 1-year clinical trial.

MEASUREMENTS

Self-reported drinking pattern and the seven composite scores from the addiction severity index (ASI).

FINDINGS

A total of 42 (57%) and 45 (61%) patients (P > 0.05) completed the Minnesota treatment and public treatment, respectively. Throughout the whole 12-month follow-up period, 35% of the patients treated at the Minnesota day clinic were abstainers, while this was the case for 20% of the patients treated in the public out-patient alcohol clinic (P = 0.043). During the last month before the end of the 1-year follow-up, 53% of the patients treated according to the Minnesota model were abstainers, while this was the case for 43% of the patients treated in the public out-patient alcohol clinic (P = 0.249). There were insignificant differences in the seven ASI scores.

CONCLUSIONS

Twelve months after onset of treatment, the Minnesota day clinic treatment does not differ in effect from the much cheaper 'standard' public treatment. However, patients in Minnesota treatment were total abstainers throughout a longer period.

Laboratory Markers Carbohydrate-Deficient Transferrin, γ-Glutamyltransferase, and Mean Corpuscular Volume Are Not Useful as Screening Tools for High-Risk Drinking in the General Population: Results From the Study of Health in Pomerania (SHIP)

BACKGROUND

Assessment of high-risk drinking in the general population can be problematic: questionnaire-based instruments may carry the problem of random or systematic recall bias, and the effectiveness of screening of single biomarkers has been shown to be insufficient. In this article, we analyze the alcohol intake/biomarker relationship of carbohydrate-deficient transferrin (CDT), gamma-glutamyltransferase (GGT), and erythrocyte mean corpuscular volume (MCV). Specific aims were (1) screening effectiveness comparison of GGT, CDT, and MCV in terms of sensitivity, specificity, and positive (PPVs) and negative predictive values (NPVs) and the effect of covariates on these measures; (2) the comparison of summary measures for the effectiveness of screening: the receiver characteristic curve (ROC) and the area under the ROC; and (3) to answer the question of which covariates effect which biomarkers and whether accounting for relevant covariates increases the prognostic value of biomarkers to levels that allow for application in the general population.

METHODS

In a representative cross-sectional health survey in northeast Germany with data collection from 1997 to 2001, 4310 men and women were asked for their recent alcohol consumption and smoking. Biomarkers were analyzed from blood samples. The effectiveness of screening of CDT, GGT, and MCV for high-risk drinking (men: >60 g/day, women: >40 g/day) was analyzed with PPV and ROC curve analysis.

RESULTS

For all three biomarkers, PPVs for high-risk drinking are very low (< 50%). There are some effects of covariates on screening effectiveness and on PPV, and knowledge of these covariates increases screening effectiveness, but no subgroup that had a combination of covariate levels and prevalence of high-risk drinking that led to a PPV > 50% could be found.

CONCLUSIONS

: Accounting for covariates in the screening procedure does not lead to a sufficient increase in PPV. Screening effectiveness of laboratory markers CDT, GGT, and MCV is insufficient for their application as screening tools for high-risk alcohol drinking in the general population. This was found using self-reported alcohol consumption as an imperfect gold standard, which is a limitation of the study, although self-reports are the standard instrument in comparable epidemiologic studies.

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

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

Should we use carbohydrate deficient transferrin as a marker for alcohol abusers?

Carbohydrate deficient transferrin (CDT) is one of the conventional markers for chronic alcohol consumption, is used by researchers and clinicians. A number of enzymes are affected by ethanol intake. The induction or inhibition of sialyl transferase and plasma sialidase may be involved in the CDT level elevation. An alteration of protein transport during post-translational modification could be a primary mechanism in the impairment of protein metabolism associated with chronic alcohol abuse. Transferrin being a steroid responsive protein, sex-based hormonal variations might contribute to the lower sensitivity of CDT. Varying hormonal statuses such as pregnancy, use of contraceptives, menopause/ menstrual cycle can alter iron homeostasis in women. CDT levels are markedly affected by iron homeostasis. Several CDT assay methods appeared promising, but it is not readily apparent which technique is the most accurate. Moreover, false-positive results of CDT have been reported in non-alcohol related hepatic failure and in rare conditions. Therefore clinical interpretation of CDT needs careful assessment in patients with alcohol-related or non-alcohol-related health disorders.

Epidemiologic evidence for the cardioprotective effects associated with consumption of alcoholic beverages

The impact of alcohol intake on mortality from all causes has been described in a large number of prospective population studies from many countries. Most have shown a J-shaped relation between alcohol intake and subsequent mortality, indicating that there are both beneficial and harmful effects of ethanol on health. The risk of death from ischemic heart disease is seen to be significantly increased, and highest among abstainers, but not significantly increased among heavy drinkers. Some studies have found plausible mechanisms for the beneficial effect of light to moderate drinking. Subjects with a moderate alcohol intake have a higher level of high density lipoprotein than abstainers. Further, moderate drinkers are seen to have a lower low density lipoprotein. Also, alcohol has a beneficial effect on platelet aggregation, and thrombin level in blood is higher among drinkers than among non-drinkers. In the other end of the range of intake, the ascending leg of the U-shaped curve has been explained by the increased risk of cirrhosis, pancreatitis, and development oropharynx, oesophagus, and breast cancer. In exploring the French paradox, it has been suggested that wine may have beneficial effects additional to that of ethanol. Recently, several prospective population studies have supported this idea. It is, however, also likely that the apparent additional beneficial effect of wine on health in addition to the effect of ethanol itself is a consequence of confounding.

Use of biomarkers for alcohol use disorders in clinical practice

BACKGROUND

Biomedical markers may provide additive objective information in screening and confirmation of acute or recent consumption, intoxication, relapse, heavy drinking, hazardous/harmful use/abuse and dependence and alcohol use related organ dysfunction (alcohol use-related disorders: AUDs).

AIMS

To review the use of biomarkers in clinical practice to detect AUDs.

FINDINGS

About one-fifth of the patients seen in clinical practice have AUDs, which offer a variety of treatment options if diagnosed. The diagnosis of AUDs relies on clinical and alcohol-related history, physical examination, questionnaires and laboratory values. No clinical available laboratory test [e.g. for acute abuse: alcohol in blood or breath; for chronic alcohol abuse: gamma-glutamyl transferase (GGT), mean corpuscular volume (MCV), carbohydrate-deficient transferrin (CDT)] is reliable enough on its own to support a diagnosis of alcohol dependence, harmful use or abuse. Sensitivities, specificities and the predictive values may vary considerably according to patient and control group characteristics (e.g. gender, age or related comorbidity). In patient groups with limited cooperation markers may be helpful when considering treatment options.

CONCLUSIONS

More research is needed to determine the value of markers (single or combined, with questionnaires) in the context of clinical decision-making algorithms in defined settings and with defined dichotomous outcome variables.

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.

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.

Factors influencing the relation between alcohol and mortality--with focus on wine

The impact of alcohol intake on mortality has been described in a large number of prospective population studies from many countries. Most have shown a J-shaped relation between alcohol intake and subsequent mortality, indicating that there are both beneficial and harmful effects of ethanol on health. In exploring the French paradox, it has been suggested that wine may have beneficial effects additional to that of ethanol. Recently, several prospective population studies have supported this idea. However, it is also likely that the apparent additional beneficial effect of wine on health is confounding.

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.

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.

Sialic acid: new potential marker of alcohol abuse

BACKGROUND

A number of laboratory markers are suggested for the detection and monitoring of alcohol abuse. However, there is still a need to find better indicators of alcohol abuse. Sialic acid (SA) is the name for a series of acyl-derivatives of neuraminic acids that occur as nonreducing terminal residues of glycoproteins or glycolipids in biological fluids and cell membranes. In this study, we investigated the diagnostic value of SA as a marker of alcohol abuse.

METHODS

Sera from social drinkers (n = 38) and alcoholics (n = 77) were analyzed for sialic acid by a colorimetric assay and for carbohydrate-deficient transferrin (CDT) by a radioimmunoassay method. Mean corpuscular volume (MCV), gamma-glutamyltransferase (GGT), aspartate aminotransferase (ASAT), and alanine aminotransferase (ALAT) were determined by using routine methods.

RESULTS

The sialic acid levels of both female and male subjects were significantly (p < 0.001) increased among alcoholic subjects when compared with social drinkers. SA levels were decreased after 3 weeks of treatment. The sensitivity and specificity for SA, respectively, were 57.7 and 95.5 for women and 47.8 and 81.3 for men. The respective values for CDT were 57.7 and 95.5 for women and 78.3 and 100.0 for men; for GGT, 60.0 and 95.5 for women and 60.9 and 87.5 for men; for MCV, 52.4 and 95.5 for women and 47.8 and 100.0 for men; for ASAT, 53.8 and 95.5 for women and 43.5 and 100.0 for men; and for ALAT, 38.5 and 90.9 for women and 39.1 and 87.5 for men. Among women, SA and GGT, and among men CDT, showed the largest area under receiver operation curve.

CONCLUSION

This study indicated that sialic acid levels were elevated by high alcohol consumption and reduced during abstinence, especially among women. Thus, sialic acid seems to be an interesting marker that needs further evaluation as a diagnostic tool for alcohol abuse.

Serum and saliva levels of sialic acid are elevated in alcoholics

BACKGROUND AND METHODS

Recently, sialic acid has been suggested as a potential marker for alcohol abuse. In this study, social drinkers and alcoholics were analyzed with a modified version of Warren's method for sialic acid and traditional markers of alcohol abuse in serum (n = 38; n = 87), saliva (n = 36; n = 29), and urine (n = 37; n = 83), respectively. The alcoholics were participating in an alcohol dependency treatment program and were followed in this study for 5 weeks.

RESULTS

The sialic acid concentrations in female and male alcoholics were significantly higher in serum (p < 0.001;p < 0.001 respectively) and saliva (p < 0.05; p < 0.05) but not in urine, compared with social drinkers. The diagnostic efficiency of serum sialic acid was higher than that for traditional markers: 77% for female subjects and 64% for male subjects. The corresponding results for saliva were 72% and 53%. The sialic acid concentrations were significantly decreased during the alcohol dependency treatment program (after 5 weeks of treatment) in both females and males.

CONCLUSIONS

This study confirms that serum sialic acid is a valuable marker for detecting and monitoring alcohol abuse. This work also indicates that sialic acid in saliva could be used possibly as a noninvasive marker for alcohol abuse.

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.

Alcohol problems in a general hospital

Alcohol is a ubiquitous drug which is responsible for a substantial amount of ill health and approximately 20% of patients in a general hospital will have alcohol-related problems, although only 4% will be admitted with alcohol-caused conditions. Eight per cent of patients, however, can be expected to have sufficient neuroadaptation to be at risk of withdrawal. This level of prevalence of alcoholism in general hospital patients requires that hospitals must become expert at providing good quality care for alcohol-related problems in all areas including obstetrics, but particularly in the management of intoxication, withdrawal and the various alcohol-related diseases. This paper provides some suggested benchmarks for acceptable standards of care for alcohol problems in the acute hospital.

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.

Reported alcohol consumption and the serum carbohydrate-deficient transferrin test in third-year medical students

The serum carbohydrate-deficient transferrin (CDT) test was performed on 143 third-year medical students along with questionnaires for the self-reporting of alcohol consumption during the last 2 weeks, the last 6 months, and questions on any alcohol-related untoward events. We found that the CDT test has poor sensitivity for detecting binge drinking in our population of students, despite some likely under-reporting of drinking. Self-reporting of drinking is commonly unreliable, and we found no significant correlation between the CDT concentrations in serum and the magnitude of self-reported alcohol use during 2-week and 6-month periods. Hangover was by far the commonest self-reported untoward event, and there was a highly significant relationship (P < 0.001) between drinking and untoward events. From a small population of non-drinkers, we estimated the reference ranges for CDT to be <27 U/l for men and <35 U/l for women.

Comparison of the Axis %CDT TIA and the CDTect method as laboratory tests of alcohol abuse

Carbohydrate-deficient transferrin (CDT) has been suggested as a specific marker of alcohol abuse. We designed this study to compare the conventional CDTect method (Pharmacia & Upjohn) and the new semiautomated Axis %CDT turbidimetric immunoassay (%CDT TIA) for their diagnostic performance to identify problem drinking. The sensitivities of the %CDT TIA and CDTect for correctly classifying heavy drinkers (n = 90) were 29% and 59% with the thresholds currently recommended by the manufacturers, respectively. In the control group (n = 114), which included hospitalized patients with abnormal serum transferrin concentrations, the CDTect assay gave 21 false-positive values (18%), whereas the %CDT TIA showed 100% specificity. With the cutoff limits based on the present healthy control group (mean + 2 SD), the sensitivities of the %CDT TIA and CDTect were 61% and 86%, respectively. For men, the ROC plot area of the CDTect results in comparisons of alcohol abusers and healthy controls was significantly (P &lt;0.05) higher than that of the %CDT TIA results, whereas for women, there was no significant difference in this respect. The slope and intercept (with 95% confidence intervals) for linear regression between CDTect and %CDT TIA were 0.13 (0.12–0.15) and 1.16 (0.73–1.59), respectively (Sy‖x = 1.51, r = 0.744). CDTect results correlated positively with serum transferrin (r = 0.224, P &lt;0.001), whereas the %CDT TIA results showed a slight inverse correlation with serum transferrin (r = −0.132, P = 0.07). The data suggest that CDTect is more sensitive than %CDT TIA in detecting drinking problems. However, the %CDT TIA method yields more specificity when analyzing samples from patients with high serum transferrin concentrations.

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.