Analysis cdt reviews. Determination of the transferrin fraction (CDT) (diagnosis of alcohol abuse)

Carbohydrate-deficient transferrin is a biomarker for chronic alcohol use (more than 60 grams of ethanol per day).

Deadline

Up to 8 days

What is this analysis used for?

To diagnose alcohol abuse.

When is an analysis scheduled?

For suspected alcohol abuse and monitoring for withdrawal.

Russian synonyms

Carbohydrate-deficient transferrin (UDT), carbohydrate-deficient transferrin.

English synonyms

Carbohydrate-deficient transferrin (CDT), %CDT.

Research method

High performance liquid chromatography.

Units

% (percentage).

What biomaterial can be used for research?

Venous blood.

How to properly prepare for research?

Eliminate alcohol from your diet for 24 hours prior to testing.
Do not eat for 8 hours before the analysis, you can drink pure non-carbonated water.
Completely exclude the use of drugs within 24 hours before the analysis (as agreed with the doctor).
Eliminate physical and emotional overstrain 30 minutes before the analysis.
Do not smoke for 30 minutes prior to analysis.

General information about the study

Transferrin is a whey protein whose main function is iron transport. In the blood, it is present in the form of isoforms with a different number of attached sialic acid residues (there can be up to 8 of them in a transferrin molecule). In the blood, the main form of transferrin is tetrasialotransferrin. When alcohol is consumed in large quantities, transferrin glycosylation is disturbed and the concentration of its other isoforms with fewer sialic acid residues (asialo-, mono-, disialotransferrins) increases in the blood. They are evaluated as total carbohydrate-deficient transferrin (CDT). The level of carbohydrate-deficient transferrin increases significantly with daily consumption of more than 60 grams of ethanol (4-5 alcoholic beverages or 0.75 liters of wine per day) for at least two weeks. With a single intake of high doses of alcoholic beverages, the concentration of carbohydrate-deficient transferrin in the blood does not change. The half-life of transferrin is 2 weeks, therefore, after the cessation of alcohol consumption, the indicator normalizes within the above period.

The specificity of CDT for the diagnosis of chronic alcohol abuse is 80-90%, the sensitivity is 60-70%. A high performance liquid chromatography (HPLC) study has a significant advantage over the immunological method in terms of specificity and sensitivity. CDT is measured in relative units (% of total transferrin), so the presence of anemia does not affect the result of the analysis.

Carbohydrate-deficient transferrin is a more specific marker for the diagnosis of alcoholism than gamma-glutamyl transpeptidase (GGTP) and mean cell volume (MCV). However, a separate appointment of CDT (without additional tests) as a screening is not recommended due to its lack of sensitivity. It should also be taken into account that the level of carbohydrate-deficient transferrin increases with congenital disorders of glycosylation, galactosemia, pregnancy and the use of hormonal drugs.

What is research used for?

To diagnose chronic high-dose alcohol use;
to evaluate the effectiveness of alcoholism treatment;
for monitoring abstinence in order to detect relapses of alcoholism;
for differential diagnosis of the causes of changes in liver function, changes in behavior.

When is the study scheduled?

If alcohol abuse is suspected;
in the presence of clinical data and changes in laboratory tests that may be associated with alcohol consumption (increased GGTP, changes in the ALT / AST ratio, impaired liver function, pancreas, neuropsychiatric changes);
when monitoring patients at risk of relapse of alcoholism.

What do the results mean?

Reference values

< 1,2 % от общего трансферрина - нормальные значения;

> 2.5% of total transferrin - pathological values.

Reasons for an increase in CDT:

alcohol abuse at a dose of more than 60 grams of ethanol per day for at least two weeks;
congenital disorders of glycosylation.

What can influence the result?

The results of the study may be distorted by pregnancy, taking hormone replacement therapy, congenital glycosylation disorders (for example, carbohydrate-deficient glycoprotein syndrome type Ia), galactosemia, congenital fructose intolerance.
The study is more specific for men than for women.
Taking medications (antidepressants, disulfirams) does not cause significant changes in the result of this analysis.

Important Notes

The level of CDT decreases to normal 2 weeks after the cessation of alcohol consumption. Single doses of high doses of alcohol do not cause an increase in this indicator.

Independently: the collection of biomaterial is carried out by the patient himself (urine, feces, sputum, etc.). Another option - biomaterial samples are provided to the patient by a doctor (for example, surgical material, cerebrospinal fluid, biopsy specimens, etc.). After receiving the samples, the patient can either independently deliver them to the Diagnostic Center or call the mobile home service to transfer them to the laboratory.

Literature
- Fleming MF, Anton RF, Spies CD: A review of genetic, biological, pharmacological, and clinical factors that affect carbohydrate-deficient transferrin levels. Alcohol Clin Exp Res 2004;28(9):1347-1355.
- Golka K, Wiese A. Carbohydrate-deficient transferrin (CDT) -- a biomarker for long-term alcohol consumption. J Toxicol Environ Health B Crit Rev. 2004 Jul-Aug;7(4):319-37.
- Tavakoli H.R., Hull M., Okasinski Lt.M. Review of current clinical biomarkers for the detection of alcohol dependence. Innov.Clin.Neurosci. 2011.8.3.26-33.

[06-236 ] Determination of the transferrin fraction (CDT) (diagnosis of alcohol abuse)

5330 rub.

Order

Carbohydrate-deficient transferrin is a biomarker (more than 60 grams of ethanol per day).

Russian synonyms

Carbohydrate-deficient transferrin (UDT), carbohydrate-deficient transferrin.

SynonymsEnglish

Carbohydrate-deficient transferrin (CDT), % CDT.

Research method

High performance liquid chromatography.

Units

% (percentage).

What biomaterial can be used for research?

Venous blood.

How to properly prepare for research?

Eliminate alcohol from the diet for 24 hours prior to the study.
Do not eat for 8 hours before the study, you can drink clean non-carbonated water.
Completely exclude the use of drugs within 24 hours before the analysis (as agreed with the doctor).
Eliminate physical and emotional overstrain 30 minutes before the study.
Do not smoke for 30 minutes prior to the study.

General information about the study

Transferrin is a whey protein whose main function is to transport iron. In the blood, it is present in the form of isoforms with a different number of attached sialic acid residues (there can be up to 8 of them in a transferrin molecule). In the blood, the main form of transferrin is tetrasialotransferrin. When alcohol is consumed in large quantities, transferrin glycosylation is disturbed and the concentration of its other isoforms with fewer sialic acid residues (asialo-, mono-, disialotransferrins) increases in the blood. They are evaluated as a total carbohydrate-deficient transferrin(CDT) . The level of carbohydrate-deficient transferrin increases significantly with daily consumption of more than 60 grams of ethanol (4-5 alcoholic beverages or 0.75 liters of wine per day) for at least two weeks. With a single intake of high doses of alcoholic beverages, the concentration of carbohydrate-deficient transferrin in the blood does not change. The half-life of transferrin is 2 weeks, therefore, after the cessation of alcohol consumption, the indicator normalizes within the above period.

Carbohydrate-deficient transferrin is a more specific indicator for the diagnosis of alcoholism than and. However, a separate appointment of CDT (without additional tests) as a screening is not recommended due to its lack of sensitivity. It should also be taken into account that the level of carbohydrate-deficient transferrin increases with congenital disorders of glycosylation, galactosemia, and the use of hormonal drugs.

What is research used for?

To diagnose chronic high-dose alcohol use;
to evaluate the effectiveness of alcoholism treatment;
for monitoring abstinence in order to detect relapses of alcoholism;
for differential diagnosis of causes, behavioral changes.

When is the study scheduled?

If alcohol abuse is suspected;
in the presence of clinical data and changes in laboratory tests that may be associated with alcohol consumption (increase in GGTP, change in the ratio /, impaired liver function, pancreas, neuropsychiatric changes);
when monitoring patients at risk of relapse of alcoholism.

What do the results mean?

Reference values

No alcohol consumption for 2 weeks:

Alcohol consumption within 2 weeks: > 2.5% of total transferrin.

Reasons for an increase in CDT:

alcohol abuse at a dose of more than 60 grams of ethanol per day for at least two weeks;
congenital disorders of glycosylation.

What can influence the result?

The results of the study may be distorted by pregnancy, hormone replacement therapy, congenital glycosylation disorders (for example, carbohydrate-deficient glycoprotein syndrome type Ia), galactosemia, congenital fructose intolerance.
The study is more specific for men than for women.
Taking medications (antidepressants, disulfirams) does not cause significant changes in the result of this analysis.

Important Notes

The level of CDT decreases to normal 2 weeks after the cessation of alcohol consumption. Single doses of high doses of alcohol do not cause an increase in this indicator.

To diagnose chronic high-dose alcohol use;
To evaluate the effectiveness of alcoholism treatment;
To monitor withdrawal symptoms in order to detect relapses of alcoholism;
For differential diagnosis of the causes of liver dysfunction, behavioral changes.

What is the measurement of CDT?

The analysis is carried out on a sample of fresh serum.

The 2013 Guidelines for Diagnosis, Monitoring of Chronic Alcohol Abuse and Screening for Common Abuse Conditions state that samples should be taken to the laboratory as soon as possible for laboratory testing.

Storage of samples should be carried out at a temperature of 2-8⁰С, storage and transportation of samples at room temperature is not allowed.
If long-term (more than 1 hour) transportation of samples is required, they must be centrifuged no later than 1 hour after blood sampling.

Serum, fresh or stored in a refrigerator at a temperature of 2-8⁰С for no more than 10 days, is allowed for analysis. For longer storage, samples should be placed in a freezer (-18…-24⁰С) within 8 hours from the moment they were taken. Frozen serum is suitable for research within a month (30 days).

Serum should not be stored at room temperature. Under these conditions, the C3 component of complement is actively decomposed, and its degradation products can affect the result of the analysis.

Do not use for whole blood testing. Blood cells can damage the capillary.

Use for the analysis of a blood plasma is not allowed. Plasma fibrinogen is a significant interfering factor and invalidates the test results.

Do not use hemolyzed serum samples for analysis. Hemolysis causes distortion of the electrophoregram and makes the CDT analysis unreliable.

Why is the CDT value measured in relative units (%), but not in SI units?

Iron deficiency anemia (a significant number of diseases lead to this condition; in addition, very often women have subclinical IDA) is the cause of a compensatory increase in the total concentration of transferrin. In this case, the absolute concentration of CDT also increases, since CDT is the sum of individual transferrin fractions, which can lead to false positive results.

Limitations of using CDT?

Analysis for CDT may be unreliable in the following cases:

The patient has CDG syndrome (Congenital Glycosylation Disorder);
The presence of genetic variants of transferrin in the patient;
The presence of monoclonal components (paraproteins) in the patient;
The patient has hypergammaglobulinemia;
The patient has liver diseases in a severe stage (cirrhosis, hepatocellular carcinoma);
A hemolyzed serum sample was used for analysis;
A serum sample with traces of fibrinogen or a plasma sample was used for analysis;
For analysis, a sample collected in a tube with an anticoagulant (EDTA, citrate) was used;
An old and/or improperly stored serum sample was used for analysis.

For which patients is CDT informative?

The fraction of low-sialylated forms of transferrin (CDT) increases with daily consumption of alcohol-containing liquids in the amount minimum 60 g/day in terms of absolute alcohol (a.a.) within at least 1-2 weeks(or 50-80 g/day for 10 days). (according to Fleming et al., 2004).

How long does it take for CDT to normalize?

Depending on the amount of alcohol consumed, the CDT concentration normalizes within a maximum of 4 weeks (the half-life of transferrin is from 12 to 17.4 days).
(Stibler Borg & Joustra, 1986).

What factors (besides alcohol intake) in rare cases cause an increase or decrease in CDT in a patient?

1. Medications
Shown, that drugs (including disulfiram) do not have a significant effect to the level of carbohydrate-deficient transferrin.
(Helander A, Carlsson S. Carbohydrate-deficient transferrin and g-glutamyl transferase levels during disulfiram therapy. Alcohol Clin Exp Res 1996;20:1202–5.).
(Helander A, Husa A, Jeppsson J-O. Improved HPLC method for carbohydrate-deficient transferrin in serum. Clin Chem 2003;49:1881–90.).

2. Pregnancy
During pregnancy (especially in the 3rd trimester), there may be increase in CDT up to a false positive result.
The mechanism of this increase still remains unexplored, but various authors believe that for pregnant women, reference CDT values calculated for the general population are unacceptable.
(Changes in transferrin glycosylation during pregnancy may lead to false-positive carbohydrate-deficient transferrin (CDT) results in testing for riskful alcohol consumption. Naama Kenan, Anders Larsson, Ove Axelsson, Anders Helander. Clinica Chimica Acta 412 (2011) 129–133 ).

3. Overweight
Separate studies show that in people who are overweight and consume significant amounts of alcohol (sufficient to increase CDT), the value of carbohydrate-deficient transferrin may be low, including being within the normal range.
(BMI but not stage or etiology of nonalcoholic liver disease affects the diagnostic utility of carbohydrate-deficient transferrin. Fagan KJ1, Irvine KM, McWhinney BC, Fletcher LM, Horsfall LU, Johnson LA, Clouston AD, Jonsson JR, O'Rourke P, Martin J, Pretorius CJ, Ungerer JP, Powell EE Alcohol Clin Exp Res 2013 Oct;37(10):1771-8 doi: 10.1111/acer.12143 Epub 2013 Jul 22.)

What is the “2-3 sialo bridge” (close location on the electropherogram of 2- and 3-sialotransferrins, which does not allow accurate separation of these 2 fractions)?

The cause of this phenomenon is considered to be a violation of plasma protein glycosylation observed in patients with various liver diseases (cirrhosis, hepatitis, hepatocellular carcinoma). In this case, there is an increase in branching and fucosylation of N-glycan chains of transferrins. According to various authors, from 0.6 to 0.8% of the examined patients have this deviation. Since 3-sialotransferrin, which is included in this block, was excluded from CDT by the CDT Standardization Working Group, it is difficult to determine CDT in such patients (if these two fractions overlap significantly, it is impossible to determine CDT).
(Eva Landberg et al., 2012).

In 2014, WHO published a ranking of the world's most drinking countries, in which Russia occupies by no means an honorable fourth place in terms of per capita alcohol consumption. Drunkenness is really a scourge for our country. In a state of intoxication, suicides, traffic accidents and serious crimes are committed. Especially sad statistics on accidents committed in a drunken stupor. Today in Russia it is strictly forbidden to drive even after one glass of alcohol. A blood test will help determine whether a person is drunk or sober by 100%.

Alcohol testing

Blood testing for alcohol is a routine procedure performed daily in hundreds of laboratories and drug treatment centers across the country. Sometimes the results of the analysis are awaited with trepidation, and sometimes with horror, realizing that a positive analysis can change fate.

Most often, blood for ethanol content has to be taken by drivers who have been in a traffic accident or those who have come under the close eye of the valiant traffic police. The driver can prove his sobriety in only one way - to take a blood test, which will show whether the person took alcohol.

But not only negligent drivers get to laboratory assistants in order to donate blood. Often, such an analysis is taken from people with severe injuries in order to determine the possibility of surgical intervention or to find out the causes of a strange human condition. Sometimes an alcohol test is taken from minors, as well as from specialists who, by the nature of their activities, are required to be sober at their workplace.

Where can you do it? A blood test is performed in special laboratories at drug treatment centers or in paid medical centers.

A blood test quite accurately shows the content of pure ethanol in the blood. The calculation is carried out in thousandths of the volume of blood, known to all ppm. The ppm figure shows how much ethanol is contained in a liter of blood and tells you how much alcohol was drunk.

The effect of ethanol on the blood

When prescribing a blood test, any doctor should warn the patient that at least a day before visiting the laboratory, you should not use any preparations containing alcohol. The clinical picture of the blood can be greatly changed under the influence of alcohol-containing drinks.

So, the following indicators change their values:

the concentration of lactic acid increases;
the level of triglycerides increases, which can be regarded as the beginning of atherosclerotic changes;
uric acid levels are significantly higher than usual. This may be identified by the attending physician as the first sign of impending kidney or liver problems;
the average volume of erythrocytes increases;
an increase in total cholesterol levels;
increased levels of the enzyme gamma-glutamyl transpeptidase, which may indicate various problems with the liver.

An experienced doctor, seeing a significant excess of the data of a biochemical blood test, may suspect that the patient had gone too far with alcohol the day before, however, such analyzes may also indicate impending problems with the most important organs - the heart, kidneys, liver. Therefore, in order for the indicators to be more reliable, blood donation must take place in an absolutely sober state.
On the video about the effect of alcohol on human blood:

Methods for determining the presence of alcohol

There is a fairly strict procedure for determining alcohol intoxication:

only venous blood is taken for analysis;
the skin at the puncture site should not be wiped with alcohol-containing products;
the laboratory assistant must wear disposable gloves;
blood is collected in sterile vials.

To date, three methods for detecting alcohol by venous blood are used:

Widmark method;
enzyme analysis;
gas chromatography method.

In laboratory conditions, the drug dispensary mainly uses the last two methods of research, since they are considered more accurate.

When referring a person to a blood test for ethanol, it should be borne in mind that over time, the concentration of alcohol in the blood gradually decreases. Therefore, a blood test taken 4-5 hours after drinking alcohol can be considered non-informative. It is recommended to take a blood test for alcohol content within an hour or two after taking it on the chest.

What else you should know about donating blood for ethanol content:

The result of the analysis shows the alcohol content only at the time of blood donation.
The analysis will not show how long ago the alcoholic beverage was drunk.

However, a blood test for the presence of alcohol in the blood determines quite accurately whether a person is drunk at the time the sample was taken or sober as a glass. The most accurate method is gas chromatography.

How is the ethanol content determined in this case? It is very simple - the analysis sample is placed in a glass container, where the liquid medium gradually evaporates, leaving air in the flask, which, in turn, is examined using a special device - a chromatograph. It is in the remaining air that the ethanol content is estimated. This technique requires an expensive device and special reagents, and in most cases it is used by all laboratories licensed for blood testing.

When answering the question of which analysis shows alcohol in the blood, it is worth mentioning the enzymatic method, which is no less common. When drinking alcohol, the activity of those enzymes that process alcohol increases significantly. A non-drinker does not have these enzymes. When conducting an enzyme analysis, donated blood is placed in a test tube, divided into fractions, a glass container with serum is placed in a special analyzer. In a matter of minutes, the device determines the content of enzymes in the blood serum.

The enzymatic method also helps to determine the prescription of alcohol consumption, allows you to give an answer to how much the patient abuses alcohol-containing products. Perhaps the intake of ethanol took place only in this case - enzyme analysis will definitely answer this question.

Often, the enzymatic method for determining ethanol is used in narcology to control alcoholic patients who have undergone treatment for abuse. The patient may claim that he does not drink alcohol, but he will be given the results of the analysis, which will show the presence of enzymes.

The Widmark method is rarely performed by forensic doctors due to incorrect results. In this case, the formula proposed by the Swedish scientist does not take into account the amount of alcohol that did not have time to be absorbed into the blood due to any reason. More often, the Widmark technique is used in the study of blood in dead people.

The method involves placing blood in special flasks and creating conditions for the oxidation of ethanol. At the same time, the degree of intoxication is calculated according to the formula proposed by the scientist, taking into account the weight of the patient, the amount of alcohol consumed and the coefficient calculated by Widmark himself.

Deciphering indicators

Any of the proposed methods establishes the amount of ppm contained in the patient's blood. The degree of intoxication in each case is determined by doctors. As a rule, doctors are guided by the table proposed by the Ministry of Health of the Russian Federation.

According to the table of the degree of intoxication, they are calculated as follows:

0.00 - 0.3 ppm - sobriety. This amount of ethanol in the blood is considered insignificant and fully corresponds to the level of endogenous alcohol produced by the body;
0.3 - 1.0 ppm - euphoric state. Coordination and perception are slowed down, a person becomes self-confident and arrogant, denies being intoxicated. Intoxication is considered light;
0.8 - 2.0 - excitement, inappropriate behavior. The reaction is slowed down, there is nausea, severe drowsiness, a person cannot adequately assess the environment. Moderate intoxication;
1.4 - 2.4 - a state of disorientation. A strong degree of intoxication, characterized by a violation of orientation in space, speech, vision. The drunk is characterized by feelings of anger and fear, insensitivity to pain. In some patients, this amount of alcohol in the blood can lead to coma;
2.2 - 3.2 - numbness and apathy. With this degree of intoxication, a person cannot move, a strong gag reflex is observed, paralysis and coma may occur. Intoxication turns into severe intoxication;
3.0 - 4.0 - severe alcohol poisoning, in most cases leading to loss of consciousness, body temperature decreases, reflexes are absent. In the absence of medical care, death is possible;
3.8 ppm and above is fatal. Alcohol poisoning is considered fatal, breathing stops, the patient dies.

The degree of intoxication of a person

What can affect the results?

Sometimes incidents happen in the work of forensic doctors and laboratory assistants - a significant amount of ethanol is found in the blood of an absolutely sober person, thereby equating it with malicious violators of traffic rules or public order.

This can happen in some cases:

In case of incorrect analysis. The laboratory assistant, violating the established rules, can wipe the skin at the injection site with alcohol.
High levels of acetone in the blood in diabetes.
Taking alcohol-containing drugs - syrups, herbal tinctures.
The use of toxic substances containing methyl or isopropyl alcohol.

A blood test for alcohol shows its content in the blood at the time of the test. Alcohol affects the results of many tests by changing the composition and parameters of the blood. It remains to figure out what exactly affects the alcohol consumed. Before which tests you can drink alcohol, and before which it is not recommended, since the data obtained will be unreliable.

Influence on the complete blood count

In a complete blood count, alcohol affects red blood cells - red cells that contain hemoglobin. Red blood cells are responsible for transporting oxygen from the lungs to all cells in the body. Alcohol destroys the outer shell of cells, due to which they cannot randomly repel each other, stick together.

The analysis will show a decrease in the number of red blood cells in the blood.
The level of hemoglobin decreases.
The viscosity of the blood increases, the formation of blood clots is possible.
Tests taken within 12 hours of drinking alcohol will show the onset of megaloblastic anemia, a deadly disease.

For these reasons, you can not take a general blood test in the morning after drinking. You can go for change if a day has passed since the last intake of alcohol, and preferably two.

Influence on biochemical analysis of blood and sugar

Under the influence of alcohol, the level of glucose in the blood is greatly reduced, which will be seen in the biochemical analysis. The most dangerous thing is to reduce sugar for people with diabetes (read -). On the other hand, many alcoholic drinks are high in sugar, especially sweet liqueurs and carbonated soft drinks. This can partially offset the destructive effect of alcohol.

Other changes in blood biochemistry results:

The concentration of triacylglycerides increases;
The concentration of lactate and uric acid increases;
The liver produces less lipids, blood plasma parameters deteriorate;

Prolonged alcohol abuse leads to a chronic change in the composition of the blood, which will be seen in the tests. In most cases, it is enough not to drink for 2-3 days so that the biochemical picture of the blood begins to correspond to reality - the normal state of the body of the subject.

Influence on hormones and other indicators

Hormone analysis. The accuracy of the determination of immune and stress hormones of the adrenal glands is impossible during or after intoxication. By itself, alcohol for the human body is a toxic substance that causes severe stress. This will significantly affect the hormonal background and research results.
Bacterial and viral studies. There may be a significant distortion of data and false-positive results for STDs, hepatitis, HIV and other studies of a similar nature. Alcohol affects tests for hepatitis, syphilis, and other important studies, so its intake should be excluded at least three days before the study. According to a number of data, even an analysis for oncomarkers can be false, although this test itself often gives false results and is not a guaranteed method for diagnosing oncology.
Analysis for microelements and macroelements. Alcohol has a diuretic effect, removes minerals and metals from the body. All analyzes will be inaccurate or false. It is possible to prescribe a treatment that is useless or even harmful to the patient.
Thyroid hormones. All research results will be significantly distorted and will not give a clear picture. The thyroid gland is very much affected by alcohol, along with the liver. It is forbidden to drink alcohol a few days before the study.

Blood test for CDT (CDT)

The SDT marker allows for the identification of chronic alcohol abuse. According to narcologists, the study helps even in the early stages of the development of alcoholism. Since this test is designed for a specific purpose and has nothing in common with other blood tests, it is unlikely to be fooled.

SDT markers break down at least two weeks, or even up to 17 days after drinking, so to get a negative result with regular use, you need to not drink for at least half a month, or even a month. Which, in turn, contradicts the definition of alcohol dependence.

Conclusion: Alcohol is a strong poison for humans, it disrupts the functioning of organs and the biochemistry of the body. Almost all existing analyzes are distorted or may give a false result after drinking strong drinks. Before donating blood, you should not drink for at least 2-3 days to get a true result.

Women's Portal Flero