IFCC approved HPLC reference measurement procedure for the alcohol consumption biomarker carbohydrate-deficient transferrin (CDT): Its validation and use

Alcohol consumption and liver phenotype of individuals with alpha-1 antitrypsin deficiency

BACKGROUND AND AIMS

Alpha-1 antitrypsin deficiency is an inherited disorder caused by alpha-1 antitrypsin (AAT) mutations. We analysed the association between alcohol intake and liver-related parameters in individuals with the heterozygous/homozygous Pi*Z AAT variant (Pi*MZ/Pi*ZZ genotype) found in the United Kingdom Biobank and the European Alpha1 liver consortium.

METHODS

Reported alcohol consumption was evaluated in two cohorts: (i) the community-based United Kingdom Biobank (17 145 Pi*MZ, 141 Pi*ZZ subjects, and 425 002 non-carriers [Pi*MM]); and (ii) the European Alpha1 liver consortium (561 Pi*ZZ individuals). Cohort (ii) included measurements of carbohydrate-deficient transferrin (CDT).

RESULTS

In both cohorts, no/low alcohol intake was reported by >80% of individuals, while harmful consumption was rare (~1%). Among Pi*MM and Pi*MZ individuals from cohort (i), moderate alcohol consumption resulted in a <30% increased rate of elevated transaminases and ~50% increase in elevated gamma-glutamyl transferase values, while harmful alcohol intake led to an at least twofold increase in the abnormal levels. In Pi*ZZ individuals from both cohorts, moderate alcohol consumption had no marked impact on serum transaminase levels. Among Pi*ZZ subjects from cohort (ii) who reported no/low alcohol consumption, those with increased CDT levels more often had signs of advanced liver disease.

CONCLUSIONS

Pi*MZ/Pi*ZZ genotype does not seem to markedly aggravate the hepatic toxicity of moderate alcohol consumption. CDT values might be helpful to detect alcohol consumption in those with advanced fibrosis. More data are needed to evaluate the impact of harmful alcohol consumption.

Recommendations on the measurement and use of the alcohol consumption biomarker CDT. A position paper from the IFCC Working Group on CDT standardisation

BACKGROUND

Carbohydrate deficient transferrin (CDT) is a biomarker for excessive alcohol consumption utilized in clinical and forensic medicine and workplace testing. Previously, many different analytical methods for CDT were used and the measurand varied considerably, making direct comparison of test results difficult. To end this confusion, the IFCC established a working group on CDT standardisation (WG-CDT) which completed its tasks in 2017.

METHODS

This IFCC position paper by the WG-CDT summarizes state of the art information about the measurand and the analytical methods and gives concise recommendations for its utilization.

RESULTS

The results achieved by the CDT standardisation process led to accuracy improvements in national external quality assessment schemes over the years. A brief review of ROC based comparison studies with the traditional biomarkers (GGT, MCV, ALT and AST) discusses the bias resulting from inadequate study populations. In large groups of the general population the superior diagnostic performance of CDT is confirmed.

CONCLUSION

The relationship between alcohol intake versus resulting CDT is discussed as well as the cutoff and measurement uncertainty. Concerning the application in practice, potential pitfalls are considered and recommendations handling both analytical and preanalytical caveats are given. Finally, some examples of serious misunderstandings in publications about CDT are addressed.

"Hide and seek": Misleading transferrin variants in PMM2-CDG complicate diagnostics

PURPOSE

Congenital disorders of glycosylation (CDG) are one of the fastest growing groups of inborn errors of metabolism. Despite the availability of next-generation sequencing techniques and advanced methods for evaluation of glycosylation, CDG screening mainly relies on the analysis of serum transferrin (Tf) by isoelectric focusing, HPLC or capillary electrophoresis. The main pitfall of this screening method is the presence of Tf protein variants within the general population. Although reports describe the role of Tf variants leading to falsely abnormal results, their significance in confounding diagnosis in patients with CDG has not been documented so far. Here, we describe two PMM2-CDG cases, in which Tf variants complicated the diagnostic.

EXPERIMENTAL DESIGN

Glycosylation investigations included classical screening techniques (capillary electrophoresis, isoelectric focusing and HPLC of Tf) and various confirmation techniques (two-dimensional electrophoresis, western blot, N-glycome, UPLC-FLR/QTOF MS with Rapifluor). Tf variants were highlighted following neuraminidase treatment. Sequencing of PMM2 was performed.

RESULTS

In both patients, Tf screening pointed to CDG-II, while second-line analyses pointed to CDG-I. Tf variants were found in both patients, explaining these discrepancies. PMM2 causative variants were identified in both patients.

CONCLUSION AND CLINICAL RELEVANCE

We suggest that a neuraminidase treatment should be performed when a typical CDG Tf pattern is found upon initial screening analysis.

Defining trimester-specific reference intervals for carbohydrate deficient transferrin in pregnant women

OBJECTIVES

Extensive consumption of alcohol during pregnancy can lead to severe complications for the unborn child. Carbohydrate-deficient transferrin (CDT) levels in serum have become a common biomarker for excessive alcohol intake. However, during pregnancy CDT levels can rise to levels above commonly used cut-off values, for reasons unrelated to alcohol intake. The aim of this study is to investigate the changes in CDT values during pregnancy and to determine accurate, trimester dependent reference intervals.

METHODS

439 serum samples of 147 healthy pregnant women were obtained for trimester 1, 2, 3, and post-partum and were analysed by high-performance liquid chromatography (HPLC) and an N-Latex immunonephelometric assay. New trimester-specific reference intervals were established.

RESULTS

This study demonstrates there is a trimester-dependent increase of %CDT, as up to 39.4% of the population exceeded the previously established upper reference limit of 1.7%. In our study the estimated upper reference limit for %DST/%CDT were 1.55%, 1.96%, 2.05% and 1.35% for trimester 1, 2, 3 and post-partum for the HPLC-method and 2.02%, 2.19%, 2.19% and 1.96% for the N-Latex immunoassay.

CONCLUSIONS

We demonstrate that CDT levels rise during pregnancy. The magnitude of the increase is method-dependent and needs to be taken into account. We have established method- and trimester-specific reference intervals to prevent false-positive results in alcohol abuse screening tests during pregnancy.

Carbohydrate-Deficient Transferrin (CDT) as a Biomarker of Alcohol Abuse: A Retrospective Study of the Italian Drinking Trend among Drivers from 2016 to 2022

Alcohol abuse is still one of the leading causes of death worldwide. Early diagnosis of alcohol abuse enables preventive intervention on the effects and risks associated with its consumption. Carbohydrate-deficient transferrin (CDT) is one of the most reliable biomarkers of chronic alcohol misuse. We retrospectively studied a population of 12,624 subjects who had their driving license suspended for driving under the influence of alcohol or drugs from 2016 to 2022. The analytical determination of CDT was performed following a certified high-performance liquid chromatography (HPLC) method. Data were split by year, age and gender. The majority of subjects with positive %CDT were male, although the trend of positivity was similar between males and females. A steady increase in both the number of tests performed and the number of positives was observed over the years. Patients aged 41-50 years had the highest prevalence, followed by 51-60, 31-40 and 18-30 years. CDT continues to be a steady marker for diagnosis of alcohol abuse in the majority of cases. Data emerging from our study are in line with the increasing national trends on traffic accidents, injuries and deaths related to alcohol and drug DUI (driving under the influence), requiring the implementation of preventive measures to limit this ever-growing phenomenon.

High CDT without clinical context: beware of the variant

Carbohydrate-deficient transferrin (CDT) is a performant biomarker used for the diagnosis of chronic alcohol abuse. Here, we describe the case of a 39-year-old male of Tamil ethnicity who had extremely elevated (20%) CDT using capillary electrophoresis (but without glycoforms profile analysis), putting his driving license regranting at risk. However, the patient had no symptoms of chronic alcohol abuse, normal mean corpuscular volume and gamma-glutamyl transferase, and did not admit to any alcohol consumption. Re-analysis by N-Latex CDT immunoassay revealed a CDT at 1.7%. Further investigation by whole-exome sequencing revealed a c.1295A>G missense variant at the heterozygous state on the TFgene. This variant is characterized by an amino-acid change at a consensus sequence forN-glycosylation. Therefore, half of the patient transferrin proteins were lacking a completeN-glycan chain out of two, despite no alcohol consumption. This also explains the discrepancies between the techniques, as the N-Latex antibodies did not recognize the mutated sequence. In conclusion, this case highlights the importance of comparing laboratory results between themselves and the clinical description, the absolute requirement for glycoforms profile analysis before delivering results, and the necessity to confirm intriguing results by another technique in a specialized laboratory.

New evidence of high association between carbohydrate deficient transferrin (CDT) and alcohol-related road traffic accidents. A retrospective study on 929 injured drivers

BACKGROUND

It is well known that traffic injuries still represent one of the main causes of death and that high blood alcohol concentrations while driving significantly increase the occurrence of accidents. However, only limited literature on the correlation between chronic alcohol abuse and accident risk is available. The aim of the present study was to investigate the hypothesis of an association between elevated concentrations of carbohydrate deficient transferrin (CDT) and the occurrence of alcohol-related traffic accidents.

METHODS

The analytical determinations of BAC and CDT were performed following certified methods in HS-GC-FID and HPLC, respectively. For BAC, 0.50 g/L was used as cut-off, whereas 2.0% was used for CDT, according to the standardisation proposed by IFCC. A total of 929 drivers, tested for BAC at the time of hospital admission after a traffic accident, were classified into two groups: InjDr 1 (BAC ≤ 0.50 g/L) and InjDr 2 (BAC>0.50 g/L); all drivers were also tested for CDT.

RESULTS

InjDr 1 included 674 individuals, only 2.5% showing a CDT above the cutoff, whereas InjDr 2 group consisted of 255 subjects, 28.6% testing positive for CDT (Odds Ratio 15.5). When subdividing the InjDr group into increasing classes of CDT, a steady increase in the percentage of BAC-positive drivers was appreciated. Moreover, average BAC was found to parallel each class of CDT.

CONCLUSIONS

The reported data strongly support the use of CDT as a biomarker of increased risk of alcohol-related traffic accidents in the procedures of re-granting of the driving license upon confiscation for "drink driving".

Self-reported alcohol consumption, carbohydrate deficient transferrin and risk of cardiovascular disease: The PREVEND prospective cohort study

BACKGROUND

Self-reported alcohol consumption is an established risk factor for cardiovascular disease (CVD). Carbohydrate deficient transferrin (CDT) is an established objective marker of excessive alcohol consumption, but data on its prospective association with CVD are lacking. We aimed to evaluate the associations of self-reported alcohol consumption and CDT (expressed as %CDT, a more reliable marker than absolute CDT levels) with CVD risk.

MATERIALS AND METHODS

In the PREVEND prospective study of 5,206 participants (mean age, 53 years; 47.7% males), alcohol consumption by self-reports, absolute CDT measured using the Siemens nephelometric assay and %CDT calculated as the percentage of total transferrin concentrations, were assessed at baseline. Alcohol consumption was classified into 5 categories: abstention (reference), light, light-moderate, moderate and heavy alcohol consumption.Hazard ratios (HRs) (95% confidence intervals [CI]) for first CVD events were estimated.

RESULTS

Mean (SD) of %CDT was 1.59 (0.54) %. During a median follow-up of 8.3 years, 326 first CVD events were recorded. Compared with abstainers, the multivariable-adjusted HRs (95% CIs) of CVD for light, light-moderate, moderate and heavy alcohol consumption were 0.66 (0.46-0.95), 0.83 (0.62-1.11), 0.83 (0.61-1.14) and 0.80 (0.48-1.36), respectively. Light alcohol consumption was associated with reduced coronary heart disease risk 0.62 (0.40-0.96), whereas light-moderate alcohol consumption was associated with reduced stroke risk 0.45 (0.24-0.83). The association of %CDT with CVD risk was not significant.

CONCLUSIONS

Our findings confirm the established association between self-reported light to moderate alcohol consumption and reduced CVD risk. However, %CDT within the normal reference range may not be a risk indicator for CVD.

A Comparison of the Predictive Power of DNA Methylation with Carbohydrate Deficient Transferrin for Heavy Alcohol Consumption

Currently, the most commonly used biomarker of alcohol consumption patterns is carbohydrate-deficient transferrin (CDT). However, the CDT has limited sensitivity and requires the use of blood. Recently, we have shown that digital DNA methylation techniques can both sensitively and specifically detect heavy alcohol consumption (HAC) using DNA from blood or saliva. In order to better understand the relative performance characteristics of these two tests, we compared an Alcohol T-Score (ATS) derived from our prior study and serum CDT levels in 313 (182 controls and 131 HAC cases) subjects discordant for HAC. Overall, the Receiver Operating Characteristic (ROC) area under the curve (AUC) analyses showed that DNA methylation predicted HAC status better than CDT with AUCs of 0.96 and 0.87, respectively (p < 0.0001). The performance of the CDT was affected by gender while the ATS was not, while both were affected by age. We conclude that DNA methylation is a promising method for quantifying HAC and that further studies to better refine its strengths and limitations are in order.

Evaluation of carbohydrate-deficient transferrin measurements on the V8 capillary electrophoresis system and comparison with the IFCC approved HPLC reference method and N-Latex immunonephelometric assay

OBJECTIVES

Carbohydrate-deficient transferrin (CDT) measurements are commonly used for the identification and follow-up of individuals suspected of chronic alcohol abuse. This study describes the analytical characteristics of the CDT assay on the Helena Biosciences V8 electrophoresis analyzer and compares its diagnostic performance to the International Federation of Clinical Chemistry and Laboratory Medicine approved high performance liquid chromatography (HPLC) method and the N-Latex CDT immunonephelometric assay.

METHODS

The analytical performance of the V8 assay, including the linearity and the imprecision, was studied at two separate locations. Method comparison analysis was performed by studying the correlation, bias and agreement between the V8, HPLC and the N-Latex assays in 231 patient samples.

RESULTS

The total imprecision ranged between 5.1 and 24.3% and was ≤13.1% for samples with concentrations above the clinical cut-off value (≥1.62%). The method comparisons revealed excellent correlations with r²≥0.97 for all comparisons. Measurements on the V8 showed a bias of -0.83 (-22.24%) and -0.40 (-12.26%) with the HPLC and N-Latex assays, respectively. The assays showed excellent agreements (Kappa scores ≥ 0.8) in classifying subjects with elevated CDT values. Receiver operating characteristic (ROC)-curve analysis, using the HPLC classification as reference, revealed areas under the ROC-curves of 0.981 (95% CI, 0.97-0.99) and 0.996 (0.99-1.00) for the N-Latex and V8 assays, respectively.

CONCLUSIONS

CDT measurements on the V8 assay are highly correlated with both the HPLC and the N-Latex assay and show excellent agreement in classifying subjects with elevated CDT values. Overall, the V8 CDT analysis is a robust, reliable and effective method to measure CDT concentrations in serum samples.

The Utility of Carbohydrate-Deficient Transferrin in Identifying Chronic Alcohol Users in the Injured Patient: Expanding the Toolkit

BACKGROUND

Alcohol use remains abundant in patients with traumatic injury. Previous studies have suggested that serum carbohydrate-deficient transferrin (%dCDT) levels, relative to blood alcohol levels (BALs), may better differentiate episodic binge drinkers from sustained heavy consumers in admitted patients with traumatic injury. We characterized %dCDT levels and BAL levels to differentiate binge drinkers from sustained heavy consumers in admitted trauma patients and their associations with outcomes.

METHODS

This prospective, cross-sectional, observational study assessed %dCDT and BAL levels in admitted male and female patients with traumatic injury (≥18 y) at an American College of Surgeons Committee on Trauma level-1 center from July 2014 to June 2016. We designated patients with %dCDT levels ≥1.7% (CDT+) as chronic alcohol users and dichotomized acutely intoxicated patients using three different BAL-level thresholds. Primary outcomes included in-hospital complications, along with prolonged ventilation and intensive care unit length of stay, both defined as the top decile. Secondary outcomes included rates of drug or alcohol withdrawal and all-cause mortality. Analyses were adjusted for clinical factors.

RESULTS

We studied 715 patients (77.5% men, 60.6% ≤ 40 y of age, median Injury Severity Score: 14, 41.7% motor vehicle crashes, 17.9% gunshot wounds, 11.1% falls). While 31.0% were CDT+, 48.7% were BAL>0. After adjusting for CDT levels, BAL levels >0, >100, or >200 were not associated with adverse outcomes. However, CDT+ relative to patients with CDT were associated with complications (adjusted odds ratio: 1.96 [1.24-3.09]), prolonged ventilation days (3.23 [1.08-9.65]), and prolonged intensive care unit stays (2.83 [1.20-6.68]).

CONCLUSIONS

In this 2-year prospective, cross-sectional, and observational study, we found that %dCDT levels, relative to BAL levels, may better stratify admitted patients with traumatic injury into acute versus chronic alcohol users, identifying those at higher risk for in-hospital complications.

Molecularly Imprinted Synthetic Antibodies: From Chemical Design to Biomedical Applications

Billions of dollars are invested into the monoclonal antibody market every year to meet the increasing demand in clinical diagnosis and therapy. However, natural antibodies still suffer from poor stability and high cost, as well as ethical issues in animal experiments. Thus, developing antibody substitutes or mimics is a long-term goal for scientists. The molecular imprinting technique presents one of the most promising strategies for antibody mimicking. The molecularly imprinted polymers (MIPs) are also called "molecularly imprinted synthetic antibodies" (MISAs). The breakthroughs of key technologies and innovations in chemistry and material science in the last decades have led to the rapid development of MISAs, and their molecular affinity has become comparable to that of natural antibodies. Currently, MISAs are undergoing a revolutionary transformation of their applications, from initial adsorption and separation to the rising fields of biomedicine. Herein, the fundamental chemical design of MISAs is examined, and then current progress in biomedical applications is the focus. Meanwhile, the potential of MISAs as qualified substitutes or even to transcend the performance of natural antibodies is discussed from the perspective of frontier needs in biomedicines, to facilitate the rapid development of synthetic artificial antibodies.

Dose-Response Characteristics of the Alcohol Biomarker Phosphatidylethanol (PEth)-A Study of Outpatients in Treatment for Reduced Drinking

AIM

Measurement of whole-blood phosphatidylethanol (PEth) offers high sensitivity and specificity as alcohol biomarker. A remaining issue of importance for the routine application is to better establish the relationship between PEth concentration and amount and duration of drinking.

METHODS

The study included 36 subjects (32-83 years) voluntarily attending outpatient treatment for reduced drinking. At ~ 3- to 4-week intervals, they provided a diary on their daily alcohol intake and gave blood samples for measurement of PEth and carbohydrate-deficient transferrin (CDT). Whole-blood PEth 16:0/18:1 was measured by liquid chromatography-tandem mass spectrometry and serum CDT (%disialotransferrin) by high-performance liquid chromatography.

RESULTS

At start, the self-reported past 2-week alcohol intake ranged 0-1260 (median 330) g ethanol, the PEth 16:0/18:1 concentration ranged 0.05-1.20 (median 0.23) μmol/L, and the CDT value ranged 0.7-13.0% (median 1.5%). At the final sampling after 5-20 (median 12) weeks, neither reported alcohol intake nor PEth and CDT levels differed significantly from the starting values. The PEth concentration showed best association with past 2-week drinking, followed by for intake in the next last week. The changes in PEth concentration vs past 2-week alcohol intake between two successive tests revealed that an increased ethanol intake by ~ 20 g/day elevated the PEth concentration by on average ~ 0.10 μmol/L, and vice versa for decreased drinking.

CONCLUSIONS

The PEth concentration correlated well with past weeks alcohol intake, albeit with a large inter-individual scatter. This indicates that it is possible to make only approximate estimates of drinking based on a single PEth value, implying risk for misclassification between moderate and heavy drinking.

A proof-of-concept analysis of carbohydrate-deficient transferrin by imaged capillary isoelectric focusing and in-capillary immunodetection

Carbohydrate-deficient transferrin (CDT) is a reliable biomarker for chronic alcohol abuse. We developed a method for CDT analysis by capillary isoelectric focusing, followed by immunodetection directly in the capillary, in an automated fashion and on a single platform (Peggy Sue™; ProteinSimple, CA, USA). Transferrin glycoforms in serum samples, including disialo-transferrin, were separated and their apparent isoelectric points and relative percentages were determined. The relative CDT values (percent of total transferrin) matched expected values for both healthy and alcoholic samples. Because the method leveraged the sensitivity of an immunoassay, CDT was measured when serum samples were diluted up to 1200-fold, reducing the volume of serum required. Finally, the process is fully automated, with up to 96 samples analyzed per batch.

Elimination Characteristics of the Alcohol Biomarker Phosphatidylethanol (PEth) in Blood during Alcohol Detoxification

Aims

The study documented elimination characteristics of three phosphatidylethanol (PEth) homologs in serially collected blood samples from 47 heavy drinkers during ~2 weeks of alcohol detoxification at hospital.

Methods

Venous whole blood and urine samples were collected every 1–2 days during treatment. Concentrations of PEth, and of urinary ethyl glucuronide (EtG) and ethyl sulfate (EtS) to detect relapse drinking, were measured using liquid chromatography-tandem mass spectrometry.

Results

When included in the study, negative or decreasing breath ethanol concentrations demonstrated that the patients were in the elimination phase. The EtG and EtS measurements further confirmed alcohol abstinence during the study, with three exceptions. On admission, all patients tested positive for PEth, the total concentration ranging 0.82–11.7 (mean 6.35, median 5.88) μmol/l. PEth 16:0/18:1, 16:0/18:2 and 16:0/20:4 accounted for on average ~42%, ~26% and ~9%, respectively, of total PEth in these samples. There were good correlations between total PEth and individual homologs (P < 0.0001). There was no significant difference in PEth values between male and female subjects. During abstinence, the elimination half-life values ranged 3.5–9.8 days for total PEth, 3.7–10.4 days for PEth 16:0/18:1, 2.7–8.5 days for PEth 16:0/18:2 and 2.3–8.4 days for PEth 16:0/20:4.

Conclusions

The results demonstrated a very high sensitivity (100%) of PEth as alcohol biomarker for recent heavy drinking, but considerable differences in the elimination rates between individuals and between different PEth forms. This indicates that it is possible to make only approximate estimates of the quantity and recency of alcohol intake based on a single PEth value.

Asialo-transferrin: Biochemical aspects and association with alcohol abuse investigation

Asialo-human transferrin (asialo-hTf) is a glycoform of the human serum protein transferrin characterized by the lack of the sialic acid (SA) terminal unit. It is known that glycosylation micro-heterogeneity and the presence of SA are strongly involved in protein functioning and pathophysiological activities. Some hTf glycoforms are valuable biomarkers for the detection of both genetic defects of glycosylation and/or sialoform distribution changes. The detection of the carbohydrate deficient transferrin (CDT) glycoforms is currently a widely employed method for the diagnosis of chronic alcohol abuse. The physiological significance of asialo-hTf is still unclear, despite its important biological implications. The current knowledge suggests that asialo-hTf may be involved in regulation of iron transport and release at the hepatic level, which, consequently, could strongly be affected by alcohol consumption. For these reasons, a deeper understanding of asialo-hTf structure and its physiological role is required, and an improved method of its analysis would favor the detection of both chronic abuse and other habits of alcohol intake and/or misuse. Thus, suitable analytical methods possessing higher sensitivity and specificity in comparison with the currently available techniques are certainly recommended. The present review summarizes the studies on asialo-hTf structure, roles, and detection techniques mainly in relation to its possible use as a potentially additional useful biomarker of alcohol abuse, and underlines its prospective value as a forensic and diagnostic tool.

Carbohydrate-deficient transferrin: utility of HPLC in handling atypical samples uninterpretable by capillary electrophoresis

HPLC retesting allowed to resolve about half of the most common CDT patterns uninterpretable by CE. The usefulness of this approach should be evaluated in the specific context of each laboratory.

Drinking Risk Level Reductions Associated with Improvements in Physical Health and Quality of Life Among Individuals with Alcohol Use Disorder

BACKGROUND

Abstinence and no heavy drinking days are currently the only Food and Drug Administration-approved end points in clinical trials for alcohol use disorder (AUD). Many individuals who fail to meet these criteria may substantially reduce their drinking during treatment, and most individuals with AUD prefer drinking reduction goals. One- and two-level reductions in World Health Organization (WHO) drinking risk levels have been proposed as alternative end points that reflect reduced drinking and are associated with reductions in drinking consequences, improvements in mental health, and reduced risk of developing alcohol dependence. The current study examined the association between WHO drinking risk level reductions and improvements in physical health and quality of life in a sample of individuals with alcohol dependence.

METHODS

Secondary data analysis of individuals with alcohol dependence (n = 1,142) enrolled in the longitudinal, prospective COMBINE study, a multi site randomized placebo-controlled clinical trial, examining the association between reductions in WHO drinking risk levels and change in blood pressure, liver enzyme levels, and self-reported quality of life following treatment for alcohol dependence.

RESULTS

One- and two-level reductions in WHO drinking risk level during treatment were associated with significant reductions in systolic blood pressure (p < 0.001), improvements in liver enzyme levels (all p < 0.01), and significantly better quality of life (p < 0.001).

CONCLUSIONS

One- and two-level reductions in WHO drinking risk levels predicted significant improvements in markers of physical health and quality of life, suggesting that the WHO drinking risk level reduction could be a meaningful surrogate marker of improvements in how a person "feels and functions" following treatment for alcohol dependence. The WHO drinking risk levels could be useful in medical practice for identifying drinking reduction targets that correspond with clinically significant improvements in health and quality of life.

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.

Identifying chronic heavy alcohol use in emergency general surgery patients: a pilot study

Background

Chronic heavy alcohol (CHA) use has been associated with perioperative complications. Emergency general surgery (EGS) patients are not routinely screened for CHA. If screened, it is usually for hazardous use of alcohol, using a survey such as the Alcohol Use Disorders Identification Test (AUDIT). This study screened EGS patients for CHA use using serum carbohydrate-deficient transferrin (%dCDT) level, a biomarker that has been validated as an indicator for CHA use, as well as the AUDIT. The purpose of this study was to determine the percent of EGS patients with CHA (as indicated by elevated %dCDT), and the relationship between %dCDT and AUDIT. Secondary aims included comparing the characteristics of EGS patients with and without CHA use, and evaluating the association of CHA use with negative clinical outcomes.

Methods

EGS patients aged 21 and older admitted to the general surgery inpatient service of a tertiary hospital from July 2014 to June 2016 were invited to participate in this study. %dCDT levels above 1.7% were considered positive for CHA use, as were AUDIT scores ≥8.

Results

195 EGS patients were screened for inclusion and 91 (46.7%) agreed to participate. 14 (15.4%) were positive for hazardous alcohol use on AUDIT and 5 (5.5%) were positive for CHA by %dCDT. Positive predictive value of AUDIT for CHA was 21.4%. There was no correlation between positive scores on AUDIT and %dCDT.

Discussion

Identifying at risk patients early on in their hospital course may allow clinicians to institute treatments to mitigate and/or circumvent complications in such patients. This pilot study determined that 17.6% of participating EGS patients were positive for some type of alcohol misuse, but only 5.5% had CHA. Further research is needed to determine whether routine use of %dCDT would be beneficial in reducing perioperative complications in this patient population.

Level of evidence

III (diagnostic test).

The quest for equivalence of test results: the pilgrimage of the Dutch Calibration 2.000 program for metrological traceability

Calibration 2.000 was initiated 20 years ago for standardization and harmonization of medical tests. The program also intended to evaluate adequate implementation of the In Vitro Diagnostics (IVD) 98/79/EC directive, in order to ensure that medical tests are fit-for-clinical purpose. The Calibration 2.000 initiative led to ongoing verification of test standardization and harmonization in the Netherlands using commutable external quality assessment (EQA)-tools and a type 1 EQA-design, where feasible. National support was guaranteed by involving all laboratory professionals as well as laboratory technicians responsible for EQA and quality officers. A category 1 EQA-system for general chemistry analytes, harmonizers for specific analytes like hGH and IGF-1, and commutable materials for other EQA-sections have been developed and structurally introduced in the EQA-schemes. The type 1 EQA-design facilitates the dialogue between individual specialists in laboratory medicine and the IVD-industry to reduce lot-to-lot variation and to improve standardization. In such a way, Calibration 2.000 sheds light on the metrological traceability challenges that we are facing and helps the laboratory community to get the issues on the table and resolved. The need for commutable trueness verifiers and/or harmonizers for other medical tests is now seen as paramount. Much knowledge is present in the Netherlands and for general chemistry, humoral immunology and protein chemistry, a few endocrinology tests, and various therapeutic drug monitoring (TDM) tests, commutable materials are available. Also the multi sample evaluation scoring system (MUSE) and the category 1 EQA-design offer many possibilities for permanent education of laboratory professionals to further improve the between and within laboratory variation and the test equivalence.

Monitoring of transferrin isoforms in biological samples by capillary electrophoresis

Work dealing with the monitoring of transferrin isoforms in human serum and other body fluids by capillary electrophoresis is reviewed. It comprises capillary zone electrophoresis and capillary isoelectric focusing efforts that led to the exploration and use of assays for the determination of carbohydrate-deficient transferrin as a marker for excessive alcohol intake, genetic variants of transferrin, congenital disorders of glycosylation and β-2-transferrin, which is a marker for cerebrospinal fluid leakage. This paper provides insight into the development, specifications, strengths, weaknesses, and routine use of the currently known capillary electrophoresis based assays suitable to detect transferrin isoforms in body fluids. The achievements reached so far indicate that capillary zone electrophoresis is an attractive technology to monitor the molecular forms of transferrin in biological specimens as the assays do not require an elaborate sample pretreatment and thus can be fully automated for high-throughput analyses on multicapillary instruments. Assays based on capillary isoelectric focusing are less attractive. They require immunoextraction of transferrin from the biological matrix and mobilization after focusing if instrumentation with a whole-column imaging detector is not available. Interactions of the carrier ampholytes with the iron of transferrin may prevent iron saturation and thus provide more complicated isoform patterns.

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

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

Why measure carbohydrate deficient transferrin?

The acute or chronic harmful use of alcohol is among the top five risk factors for disease, disability and death worldwide.1 Monitoring alcohol consumption is an important aspect of the management of alcohol-use disorders and may include subjective self-reported questionnaires or objective tests.1,2-6 Such tests include measuring alcohol or alcohol metabolite levels or biomarkers such as liver enzymes or red cell indices.2-6 Carbohydrate deficient transferrin (CDT) is a biomarker used for assessing chronic alcohol misuse.6 Here, we review CDT and its place in the assessment of chronic alcohol use.