What does blood ldg mean? Lactate dehydrogenase (LDH) in a biochemical blood test: what it is, norms by age, what does an increase and decrease in enzyme levels mean. Changes in LDH levels in the bloodstream

It is important to consider that lactate dehydrogenase may be elevated in women during pregnancy, in professional athletes and newborn babies. In old age, there is also an increase in indicators as a result of changes in the body.

Symptoms and signs of elevated values

The increase in LDH levels alone not accompanied by specific symptoms. Depending on the cause of the change in indicators, patients may experience heart pain, changes in blood pressure and pulse, headache, weakness, drowsiness, convulsions, decreased performance, increased body temperature.

Dangers and Consequences

Significant increase in LGD indicates the presence of a pathological process in the human body. Lack of treatment or late diagnosis of the disease can lead to unpleasant consequences for the patient. Existing diseases can become severe and chronic, increasing the risk of strokes, heart attacks, and liver pathologies.

The criterion under consideration may deviate from normal values ​​in a number of different diseases. The reasons for the increase in lactate dehydrogenase concentration may be:

• myocardial infarction, accompanied by ischemic necrosis of the middle layer of muscle tissue of the heart;
• blockage of a pulmonary artery with a blood clot or pulmonary infarction;
• blood pathologies, which are characterized by the destruction of red blood cells ( different kinds anemia, hemolysis, severe intoxication);
• malignant tumors affecting various organs and tissues, often accompanied by metastasis;
• disturbances in liver function due to chronic and acute hepatitis, Gospel disease or alcohol intoxication;
• kidney pathologies (glomerular nephritis, pyelonephritis);
• muscle tissue atrophy or injury;
• open and closed fractures;
• congestive heart or coronary failure;
• inflammation of heart muscle tissue;
• mononucleosis, viral etiology;
• acute attack of pancreatitis;
• convulsive seizures;
• alcoholic delirium (mental abnormalities due to sudden withdrawal of alcohol);
• burn disease;
• premature placental abruption;
• hyperfunction of the thyroid gland.

When identifying the causes of increased LDH in women and men, it is necessary to exclude the influence of factors that can lead to unreliable results:

• improper blood sampling, resulting in the destruction of red blood cells in the test tube (hemolysis);
• neglect of the rules of preparation for the delivery of biomaterial: physical and emotional stress, smoking, alcohol, poor diet;
• the use of treatment methods accompanied by electrical stimulation of the patient a week before the analysis;
• excess platelets in the blood;
• reception medicines activating the enzyme system.

LDH and creatinine are elevated

Creatinine is a metabolite by-product amino acid-protein metabolism in the human body. It is produced by creatine molecules, which play an important role in the functioning of the muscular system. It helps to implement energy metabolism in all tissues - especially muscle tissue.

Creatinine is “born” when protein compounds are broken down and energy is released. This most often occurs during the digestion of food, during physical work, in which muscles are always involved.

After its “birth,” creatinine enters the blood, and it delivers it to the kidneys. There it is filtered and then leaves the body along with urine.

Doctors, based on data on the level of creatinine in the blood, learn about the protein metabolism and kidney condition of the patient. It can help detect many diseases in their early stages.

Acceptable norm of creatinine

The permissible norm of creatinine depends on gender, age, lifestyle, level of physical activity and hormonal processes, and the constitution of the human body. In a healthy body, the concentration of the metabolite in the blood remains stable around the clock, rising only slightly when muscles contract. Sharp jumps in creatinine are a sign of severe kidney disease.

Low creatinine - causes

Low concentration of creatinine in the blood (hypocreatinemia) is a very rare phenomenon. This is a sign of problems with protein metabolism throughout the body or just in one muscle tissue.

Renal dysfunction does not have a particular effect on the concentration of this metabolite in the blood. The problem here is different: the body’s protein resources accumulated in the muscles are depleted.

Low creatinine in itself is not a disease and does not need to be treated. There are many factors that reduce its concentration, and they can be different for men and women. Here are the common reasons for its decrease for both sexes:

What is LDH

Lactate dehydrogenase is one of the enzymes that indicates the presence of damaged cells. It is found both in the blood and in tissues in different quantities. During respiration, lactic acid salts are formed in cells. Lactate dehydrogenase promotes its transition to pyruvic acid, which is involved in the high-energy oxidation process. It promotes the rapid release of energy from glucose, which is necessary for muscle contraction and biochemical processes. The result is products that are easily removed from the body - carbon dioxide and water. If there is insufficient oxygen supply, the enzyme accumulates, causing pathologies that accelerate cell breakdown. They will cause lactate dehydrogenase to be elevated. This indicator is very sensitive to the destruction of cellular structures.

Lactate dehydrogenase, if arranged in order of decreasing quantity, is found in the following organs and tissues:

• In the kidneys.
• Cardiac muscle.
• Skeletal muscles.
• Pancreas.
• Spleen.
• The chemical laboratory of our body - the liver.
• Lungs.
• In blood serum.

Causes

As a result, studies may determine that LDH is elevated. This condition indicates abnormalities in the functioning of the body. Based on the results of one analysis, it is impossible to accurately diagnose; one can only confirm the development of pathology. To identify the true reasons why LDH is elevated, it is necessary to conduct additional instrumental studies.

Possible reasons:

• liver pathologies - most often there is an increase in indicators with cirrhosis of the liver, as well as with various changes in the structure of tissues due to alcoholism or viral hepatitis;
• infarction of the heart, kidney, lungs, intestines - with myocardial infarction, the enzyme level increases in the first two days after the attack and remains elevated for about 11-12 days. Pulmonary infarction is accompanied by chest pain and may increase LDH levels;
• oncology;
• pyelonephritis;
• blood diseases that provoke hemolysis;
• acute pancreatitis;
• lack of oxygen in the body;
• meningitis. This phenomenon can cause the development of encephalitis;
• injuries and muscle fiber atrophy;
• lymphoma;
• broken or cracked bones;
• extensive burns;
• placental abruption during pregnancy;
• hyperthermia.

The value of LDH isoenzyme indicators

If we take a closer look at the increase in lactate dehydrogenase of a certain type, we can determine the foci of a possible developing pathology.

An increase in LDH-1 or the LDH-1/LDH-2 ratio is possible in the following conditions:

• Acute heart attack.
• Hemolytic megaloblastic anemia.
• Acute kidney necrosis.
• In the presence of tumors of the male and female genital area.

An increase in LDH-5 is typical for:

• Liver diseases.
• Cancer.
• Injury to skeletal muscles.

An increase in LDH-2 and LDH-3 is usually observed with:

• Acute leukemia.
• Chronic granulocytosis.

An increase in LDH-3, possibly partially LDH-4 and LDH-5 most often occurs if there are:

• Kidney diseases.
• Pulmonary embolism.
• Heart failure developing with involvement of lung tissue.

An increase in LDH-4 LDH-5 is detected if:

• Poor circulation due to weak heart function.
• Liver damage.
• Muscle injuries.

Normal LDH level in blood

In a healthy person, the enzyme lactate dehydrogenase does not accumulate in the body, but is neutralized or eliminated naturally. But, some pathologies leading to cell breakdown will certainly lead to an increase in LDH.

There are established boundaries when they say that ldg is normal. The norm of the indicator, to a greater extent, depends on the age of the patient, since at the beginning of life the enzyme level reaches its highest values, and over the years, the blood lactate norm noticeably decreases.

So, for newborns, an LDH test is considered normal if it is less than 2000 U/liter of blood, or 2.0 µmol/h*l. In children under 2 years of age, the enzyme level is still quite high, and the norm is considered to be no more than 430 U/l. In children under 12 years of age, the norm is taken to be no more than 295 U/l. As for adults, the normal level of LDH in the blood in women is approximately 135 to 214 U/L, and in men 135-225 U/L.

Treatment

Further treatment of patients with elevated LDH levels depends on the underlying cause of the change. To begin with, the attending physician prescribes an extensive blood test, ultrasound diagnostics, MRI, CT. If liver disease is suspected, liver tests and hepatitis testing are also prescribed.

Based on the data obtained, antiviral, hepatoprotective, and immunomodulatory drugs may be prescribed.

If the cause of the deviations is anemia, then Maltofer, Sorbifer, Ferrum-Lek, Fenyuls and others are prescribed iron supplements. For oncological diseases, an integrated approach is used, which includes taking specialized medications and chemotherapy. In case of myocardial infarction, cardioprotectors and drugs that support heart function are prescribed.

It is important to know that any medications and procedures can only be prescribed by the attending physician, based on test results and individual characteristics body. Application of funds traditional medicine must also be agreed with a doctor

In combination with drug treatment prescribe a certain diet.

She rules out bad habits, eating fatty, spicy, smoked and canned foods.

Lactate dehydrogenase is elevated

As already noted, the main reason for the increase in lactate levels is the destruction of cellular structures in certain pathological conditions. LDH increased reasons:

• myocardial infarction or heart failure;
• stroke;
• pulmonary infarction or pulmonary failure;
• kidney diseases;
• cirrhosis of the liver;
• hepatitis, jaundice;
• acute pancreatitis;
• blood diseases (leukemia, anemia, etc.);
• cancerous tumors in organs;
• acute skeletal and muscle injuries (atrophy, dystrophy, etc.);
• hypoxia, oxygen deficiency in organs and tissues, respiratory failure;
• if LDH is elevated during pregnancy, in most cases this is considered normal, or it becomes a signal of placental abruption.

These are the most common cases in which a biochemical blood test reveals an elevated LDH enzyme. However, it happens that lactate dehydrogenase is elevated and the reasons for this are physiological, that is, the indicator is false and does not indicate the development of pathology in a person. Provoking factors may be:

• some skin diseases;
• heavy physical and psychological stress on the eve of the test;
• alcohol consumption;
• application of some medicines(especially insulin, aspirin, anesthetics);
• thrombocytosis.

Since each organ has so-called LDH isoenzymes (LDH1,2,3,4,5). With an increase in LDH 1 and 2, we are most likely talking about myocardial infarction, and the high concentration of the enzyme in the blood remains for 10 days after the heart attack. With an increase in LGD 1 and 3, one can suspect the development of myopathy in a person. If LDH enzymes 4 and 5 are especially active, then liver disorders can be judged, for example in acute hepatitis

Also, these isoenzymes can be increased when muscles and bones are damaged, with possible damage to internal organs. If you suspect the development of cancer, especially pay attention to the concentration of LDH 3, 4 and 5

If the LDH level increases, the doctor may prescribe an additional blood test for SDH; this analysis gives more accurate results.

Situations when LDH levels are low are extremely rare. And as a rule, an analysis with such a result has no diagnostic value. This situation is usually attributed to errors during laboratory research. Sometimes, a decrease in enzyme levels is associated with the consumption of ascorbic acid or vitamin C in large quantities.

What is the definition of LGD used for?

A study of blood lactate concentration levels is often prescribed to confirm the diagnosis. However, if earlier this diagnostic method was popular and widely used, today its role is gradually losing its importance, as it has been replaced by more accurate and reliable analysis methods. However, such studies can be very expensive and technically complex.

For research, blood is taken from a vein; it is considered the most concentrated and easier to process. After collection, the necessary serum is extracted from the blood, which is used to determine the patient’s lactate level. Test results are usually ready on the 2nd day after the study.

Thus, with the help of LDH analysis, it is possible to timely identify the presence of diseases, disorders, and pathological processes in a person even at the very beginning. early stage until characteristic symptoms appear.

Clinical significance of determining lactate dehydrogenase activity

Already a few hours after the onset of acute myocardial infarction, a significant increase in L activity is noted in the blood serum. After 36-48 hours. this activity reaches its maximum (often it is 10-15 times higher than normal). The optimal period for determining L. activity in blood serum is 2-4 days after the onset of a heart attack, since during this time period the value of this biochemical test is greatest. So, for example, its diagnostic accuracy, according to I.V. Martynov, for transmural myocardial infarction during this period of time is 97 ± 1.7%.

Typically, L.'s activity in the blood serum during a heart attack returns to normal on the 10-12th day after the onset of the disease. L.'s activity in the blood serum during myocardial infarction remains elevated longer than other enzymes (eg, aminotransferases).

The value of determining L.'s activity in blood serum is especially great in unclear cases of myocardial infarction (with an atypical wedge and electrocardiographic pictures, in particular with prolonged anginal attacks, accompanied by transient deformation of the ST segment or T wave without the appearance of patols, Q wave), as well as for differential diagnosis between myocardial infarction and dissecting aortic aneurysm, acute pericarditis and pulmonary artery thrombosis. With all these diseases, the increase in L.'s activity in the blood serum is not as sharp as with myocardial infarction.

However, the magnitude of L.’s activity does not allow us to judge with confidence the extent of damage to the heart muscle, much less predict the outcome of the disease.

In patients with angina pectoris, no increase in L.'s activity in the blood serum is observed. This allows the LDH test to be used as a reliable criterion for the absence of damage to the heart muscle within 2-3 days after a heart attack.

L.'s activity in the blood serum increases with parenchymal hepatitis in the first days of the icteric period. In mild to moderate forms of the disease, enzyme activity returns to normal fairly quickly. With obstructive jaundice, L.'s activity in the blood serum remains normal, only in the later stages of the disease does it increase due to secondary damage to the liver parenchyma. With liver carcinomas and cancer metastases to the liver, L.'s activity in the blood serum may also increase; at the same time, the concentration of pyruvate in the blood serum increases 2-3 times (the norm is 0.5-1.0 mg%). However negative result The LDH test in this case does not at all indicate the absence of malignant liver damage.

In the stage of remission hron, hepatitis, L.'s activity in the blood serum remains within normal limits or increases slightly, and increases with exacerbation of the process. In this case, the LDH test can be used as an auxiliary test along with other enzyme tests.

L.'s activity in the blood serum also increases with progressive muscular dystrophy, hron, lymphogranulomatosis, leukemia, pernicious anemia, acute and hron, nephritis, with tumors in urinary tract and other diseases.

More important in diagnosis compared to determining the total activity of serum L. is the determination of the isoenzyme composition of L.

Usually in blood serum healthy people All 5 fractions of L. are detected, the activity of which is distributed as follows: LDH2>LDG1>LDG3>LDG4>LDG5. During acute myocardial infarction, the ratio between the activities of LDH1 and LDH2 changes so that the activity of LDH1 becomes equal to or higher than the activity of LDH2. This indicator has great importance in late diagnosis of myocardial infarction. In addition, due to the specificity of this test, it can be used for differential diagnosis.

With parenchymal damage to liver tissue (infectious hepatitis), as well as with certain muscle diseases (progressive muscular dystrophy) detect a significant increase in the relative content of LDH5, which is also used in the enzyme diagnostics of these diseases.

See also Dehydrogenases.

Bibliography: Nyosholm E. and Start K. Regulation of metabolism, trans. from English, p. 111, 291, M., 1977; With e in e r and N S. E. Glycolysis, in the book: Chem. fundamentals of life processes, ed. V. N. Orekhovich, p. 156, M., 1962; Harris G. Fundamentals of human biochemical genetics, trans. from English, p. 53, M., 1973; Holbro ok J. J. a. O. Lactate dehydrogenase, in: Enzymes, ed. by P. D. Boyer, v. And, p. 191, N.Y.-L., 1975, bibliogr.

Conducting research

When the lactate dehydrogenase level is elevated, you need to focus your attention on the reasons that caused this condition. This analysis is carried out exactly the same for both adults and children.

The blood collection process does not cause pain, so parents don't have to worry. Blood is taken only from a vein, because it is the most concentrated, and for laboratory processing this is a very important indicator.

As soon as the blood is received, the laboratory assistant extracts serum from it; the remaining components are not needed for biochemical analysis. Further, after certain manipulations, you can find out whether the lactate in the baby’s blood is increased or decreased. Sometimes test results are not released immediately on the second day. The fact is that the material can be stored a little longer, the main thing is that certain conditions are met. Let’s say if the storage temperature is 20 degrees, then the whey can be stored for another month and a half.

Only the blood must be brought to the laboratory within the same two days in order to obtain serum from it in time. If all parameters are met, then the results obtained can be considered one hundred percent accurate.

To take the lactate dehydrogenase test, the patient does not need any special preparation.

But important rules don't miss:

1. Blood is taken early in the morning, on an empty stomach.
2. In terms of nutrition, you can leave everything as it is.
3. You can do sports exercises at the same rhythm, but without overworking yourself.

Otherwise, there are no special instructions. Despite the fact that the procedure is painless, it is still something unknown and unusual for children. So, before the upcoming procedure, it’s worth preparing him: talk to him calmly, tell him everything as it will happen. When the child is ready, then the procedure will seem normal.

The analysis for lactate dehydrogenase may exceed normal standards, be reduced, or be equal to normal. When LDH is elevated, we can talk about the presence of certain types of anemia, hepatitis, hypoxia, or carcinomatosis.

Whatever the doctors’ conclusion, every parent must respond to the condition of their child, because each disease has its own symptoms. The body always signals about any deviations, especially in childhood.

Also, the child has not yet had time to get used to all manifestations of the external environment. The body is just adapting to all kinds of changes. This is exactly how many doctors explain frequent illnesses younger generation. Over time, the immune system, knowing this or that irritant, is able to give its response, then infection will not occur. But preventive measures should not be forgotten; they will help increase immune defense.

How is the analysis carried out?

To assess the level of LDH and its enzymatic activity, 2 groups of methods are used:

• spectrophotometric, the essence of which is to determine the difference in the absorption spectra of the oxidized form of NAD (a coenzyme of all living cells) from the reduced one;
• colorimetric, subdivided into dinitrophenylhydrazine - determination of pyruvate concentration, and redox indicator - identification of certain molecules using indicators that change color.

An optical test is used as standards for determining the enzymatic activity of LDH, and electrophoresis is used for isoenzymes. When issuing analysis results, the laboratory must indicate the chosen method.

Normalization of LDH levels in the blood

Patients often wonder how to reduce enzyme levels? To do this, it is necessary to initially establish the exact cause of the increase in LDH. Only by eliminating the disease that was the cause is it possible to return the indicator to normal values. Therapy for each pathology has its own characteristics:

• after the first signs of myocardial infarction, a person needs to provide first aid. Any delay in treatment may lead to fatal outcome and the development of serious complications. In order to assess the risk of relapse, a control measurement of LDH levels is carried out, which should return to normal with adequate therapy;
• in case of anemia caused by iron deficiency, the patient’s diet is corrected and iron-containing drugs are prescribed. A favorable outcome is considered to be an increase in hemoglobin levels and a decrease in LDH;
• in oncopathology, large-scale screening of the patient is necessary to assess the size of the tumor, the presence of metastases and the degree of organ damage. In this case, assessment of the effectiveness of treatment includes analysis of LDH and main tumor markers. The absence of positive dynamics, expressed in a decrease in the criteria under consideration, is a reason to transfer the patient to more aggressive methods of treatment;
• in case of acute pancreatitis, it is necessary to place the patient in a 24-hour hospital. Treatment includes drips with painkillers, antibacterial and anti-inflammatory drugs. As the patient's condition improves, all biochemical parameters return to normal.

Determination of LDH levels

The blood is tested for LDH content using a special technique called the “UV test”. Blood is taken from a vein in the morning (before 10) and on an empty stomach. The resulting substance is then centrifuged to separate the serum from the plasma.

It is very important that the serum is clean, without traces of red blood cell breakdown, otherwise the result may be incorrect

Attention! It is not advisable to smoke or drink alcohol on the eve of the test. In addition, you should not eat 6-8 hours before the test, and it is necessary to limit the consumption of protein and fatty foods

Intense sports can also distort the results. The final indicator is also influenced by the medications taken, so it is worth postponing taking medications on the day of the study. Usually, the results of the analysis can be seen already on the 2nd day of the examination.

When LDH is elevated

An increase in LDH concentration occurs in the following pathologies:

• stroke
• myocardial, intestinal or lung infarction
• pulmonary failure
• hypoxia
• acute pancreatitis
• pancreatic diseases
• low blood pressure
• diseases that affect the hepatobiliary complex
• cancer of the blood, kidneys, testicles, etc.
• cirrhosis of the liver
• jaundice (in the first stages of the disease)
• iron deficiency or pernicious anemia
• eclampsia
• placental abruption
• some fungal diseases
• lymphoma
• hepatitis
• Infectious mononucleosis
• skeletal muscle injuries, traumatic shock
• dystrophic condition
• glomerulonephritis
• leukemia
• oxygen deficiency

To determine exactly where the leak is pathological process, you need to analyze which LDH isoenzyme is elevated.

An increase in LDH-1 or LDH-2 levels most often indicates a heart attack. If the concentration of LDH-1 and LDH-3 is increased, then it can be assumed that the patient is developing muscle tissue atrophy. Excessive activity of LDH-4 and 5 isoenzymes often indicates liver dysfunction, as well as muscle and bone damage

If cancer is suspected, then the greatest attention is paid to the amount of LDH-3, 4 and 5

Important! Elevated LDH levels can be found in conditions such as:

• alcohol consumption
• psychological stress or increased physical activity
• certain skin diseases
• the use of certain medications (most often aspirin, anesthetics, fluorides, oral contraceptives and insulin)
• thrombocytosis

When LDH is low

A decrease in the concentration of lactate dehydrogenase in the blood is typical in the following situations:

• consumption of large amounts of ascorbic acid;
• high levels of oxalic acid salts (oxalates) in urine
• a peculiar reaction to cystotic chemotherapy.

A decrease in LDH is very rare and is not always interpreted as evidence of the presence of disorders in the body.

Norm of LDH in the body and interpretation of the analysis

When testing blood, the norm is usually indicated in units/l, which means one per liter. The interpretation of the analysis takes into account the age and gender of the patient. A relatively small amount of the enzyme is found in the blood of a healthy adult. In a child under two years of age, the norm is considered to be within 430 units/l.

An increase in lactate dehydrogenase occurs during pregnancy, in newborns, and in professional athletes.

Based on the identified marker, it is impossible to determine which cells were damaged. Therefore, when deciphering LDH, it is necessary to know what its isoenzymes are. Some laboratories conduct additional tests that determine several forms of the substance, starting with the most mobile:

the first indicates a problem with the heart, kidneys and red blood cells;

the second is found mainly in cardiomyocytes and erythrocytes;

the third is found in lung tissue, endocrine glands and adrenal glands;

the fourth is an enzyme in white blood cells, liver, placenta and male testicles and muscle tissue;

the fifth is found in all organs containing LDH-4, as well as skeletal muscles.

Deciphering biochemistry for increased LDH in the blood is now considered less informative.

High values ​​of all isoenzymes determine the pathology of several organs. Myocardial infarction with congestive heart failure causes lung damage and liver congestion. In cancer and autoimmune diseases such as lupus, lactate dehydrogenase is generally elevated. Hypoxia, shock and burns are accompanied by cell death, which shows an increase in LDH. Caffeine also affects the amount of enzyme in the blood.

The dynamics of the first isoenzyme are more sensitive and specific than the increase in LDH in general. Usually the level of the second isoenzyme is higher than the first. If the concentration of LDH-1 increases relative to LDH-2, a heart attack is diagnosed. Typically, the LDH level in the blood is exceeded 12-24 hours after damage to heart tissue and for two days in 80% of cases. A normal LDH-1/LDH-2 ratio is reliable evidence that there was no attack. The ratio of total LDH to LDH-1 is called hydroxybutyrate dehydrogenase. Therefore, during a heart attack:

the LDH/GBDG figure is reduced (less than 1.30);

the LDH-1/LDG-2 ratio approaches 1 and sometimes exceeds this value.

On the first day, myocardial infarction is diagnosed by the creatine kinase indicator, and a day later - by the enzymatic study of LDH. The activity of the substance is directly related to the area of ​​damage to the heart muscle.

Other serious diseases are reflected in the ratio of isoenzymes and coefficients:

hemolytic anemia is characterized by a low LDH/GBDG figure - up to 1.3 and lower;

in megaloblastic anemia, LDH-1 significantly exceeds LDH-2;

the general level increases during acute necrotic processes and cell death, such as damage to the kidney parenchyma;

tumors in the gonads (ovaries and testes) are accompanied by an isolated increase in LDH-1.

Most often, LDH is elevated due to the destruction of tissue of the liver and kidney parenchyma, and the death of platelets and red blood cells.

LDH in a blood test is considered in relation to other indicators:

With anemia, red blood cells are destroyed, which releases large amounts of LDH into the blood. The disease is diagnosed against the background of low hemoglobin. Weakness, pallor, shortness of breath may be indications for examination.

Blood cancer is associated with the production of abnormal blood cells, which is reflected in the levels of many indicators: LDH, aspartate aminotransferase, bilirubin, urea. At the same time, there is a decrease in the level of glucose and the blood clotting factor fibrinogen. A biochemical blood test allows one to suspect pathology and refer the patient to identify tumor markers.

Along with the LDH level in the blood, which indicates the death of pancreatic cells, bilirubin and glucose will increase. The primary indicator is the level of the pancreatic enzyme amylase.

Causes of increased lactate dehydrogenase

LDH levels can increase for various reasons, when certain pathologies and diseases occur.

Among the reasons for increased lactate dehydrogenase values ​​are:

• Congestive heart failure.
• Myocardial infarction. When this condition appears, the concentration of LDH in the blood increases sharply in the first two days (up to 55 hours), and then persists for about 10 days, but this period is different for each patient. In one person, the elevated LDH value after a heart attack persists for 3–4 days, in another – for 7–10 days.
• Pulmonary infarction. In this case, an increase in LDH is observed almost immediately with the appearance of sharp pain in the chest area.
• Various pathological conditions of the kidneys.
• Stroke.
• Lymphoma.
• Leukemia.
• Intestinal infarction.
• Various oncological diseases.

• Anemia of various etiologies and other blood diseases accompanied by hemolysis.
• Pancreatitis in acute form.
• Infectious mononucleosis.
• Damage bone tissue, for example, bone fractures.
• Pathological conditions of muscles, in particular, atrophy, dystrophy or injury.
• Hypothermia, hyperthermia, as well as various conditions that are accompanied by hypoxia.
• State of shock when injured.
• Burns large areas skin.
• Seizures of a convulsive nature.
• Delirium tremens.
• Eclampsia.

The reason for the increase in LDH may be during pregnancy. Since increasing the indicator during this period may be an option normal value, but at the same time, this condition may also indicate the occurrence of placental abruption.

Other reasons can also cause an increase in the result (false or physiological), in particular:

• Exercise during the day before blood collection or any strenuous physical activity.
• Use of hemodialysis.
• Drinking alcoholic beverages in the days immediately before the test.
• Carrying out electropulse therapy procedures for 1-3 days before blood sampling.
• The presence in a person of a special prosthetic valve in the heart, leading to hemolysis of red blood cells.
• Some types of skin diseases.
• Presence of thrombocytosis.
• Taking certain medications that can affect the concentration of LDH in the body, in particular, non-specific anti-inflammatory drugs, anesthetics, anabolic steroids, sulfonamides, codeine, caffeine, penicillin, insulin, as well as valproic and acetylsalicylic acid.

Indications for analysis

A person can be prescribed a test for LDH in the blood if:

• Diagnosing heart or lung diseases when the patient has complaints of frequent and severe pain in the chest area, as well as when myocardial infarction is detected.
• Carrying out diagnostics of muscle pathologies and malignant tumors.
• Carrying out comprehensive surveys to determine the general condition.
• Monitoring the treatment of various oncologies, assessing the effectiveness of therapy, as well as monitoring the development of certain ailments.
• If there is a suspicion that the patient has cell and tissue damage in a chronic or acute form.

The study has particular diagnostic value for:

• General diagnostics during complex examinations.
• Diagnosis of heart attacks, primarily of the heart muscle, as well as lungs and other organs.
• Diagnosis of angina pectoris.
• Detecting diseases that are accompanied by the process of hemolysis of red blood cells.
• Diagnosis of pathologies of certain organs, for example, kidneys or liver, as well as muscle tissue.

Also, the study is often carried out by cancer patients to monitor the development of tumor processes and determine the degree of effectiveness of the therapy.

The LDH (lactate dehydrogenase) test is a nonspecific test that is used when a number of diseases and conditions are suspected. The enzyme enters the blood plasma during the destruction of almost any cell in the body, including bacterial ones. Therefore, the level of LDH in the blood is overall indicator tissue and cellular damage. Sometimes the concentration of a substance is assessed using cerebrospinal or pulmonary fluid in the presence of certain diseases.

The importance of the enzyme in the body

Interest in what LDH is in a biochemical blood test is associated primarily with myocardial infarction. Previously, this test was used to diagnose and monitor damage to cardiac tissue, but now the troponin test is considered more accurate and informative. Lactate dehydrogenase (LDH) is not a specific indicator of cardiac cell damage and is no longer used in patients with suspected acute coronary syndrome. Typically, the transcript of a biochemical blood test contains this indicator. Lactate dehydrogenase in the blood is an important enzyme involved in the reactions:

Glucose oxidation;

Lactic acid production.

The peculiarity of the enzyme is that it does not accumulate in cells, but is completely broken down and excreted. LDH is essential for converting glucose into energy for the functioning of all cells in the body. The reaction is mediated by oxygen, which helps break down glucose into water, carbon dioxide and energy. Without oxygen, energy production decreases by 20 times and lactic acid accumulates. The enzyme LDH is necessary for its oxidation and return to glucose metabolism. Unlike healthy cells, cancerous tumors feed without oxygen.

When is the test prescribed?

The test is used when acute and chronic tissue damage is suspected, as well as to evaluate progressive diseases. In rare cases, the test can help identify target organ damage.

The enzyme is determined in a venous blood sample. After injury, LDH is elevated, rises for 48 hours and reaches a maximum after 2-3 days, then gradually decreases. The normal level is restored within 10 days.

Research shows that the LDH blood chemistry test is an indicator of cancer development and progression. Even after taking into account the factor of age and stage of the disease in patients, a strong association with the risk of death remained. This relationship was true for all types of malignant tumors.

The blood LDH test can be used to detect and evaluate:

Acute or chronic tissue damage;

Progression of anemia and severe infection;

Courses of cancer after chemotherapy, leukemia, melanoma, neuroblastoma. At high values indicates poor prognosis for patient survival.

The doctor prescribes determination of LDH levels in other body fluids:

To distinguish between bacterial and viral meningitis by analysis of cerebrospinal fluid.

To identify the cause of the accumulation of fluid in the chest or abdomen (pleural, peritoneal and pericardial fluids) due to trauma and inflammation or due to an imbalance of pressure within blood vessels and the amount of protein in the blood.

A blood test for LDH (biochemistry) is taken on an empty stomach from a vein.

The last meal 8 hours before the examination should not contain too much fatty or protein foods.

Be sure to inform if you need to take medications regularly. Aspirin, hormonal contraceptives and antidepressants affect clotting and may show elevated values.

Intense training the day before can lead to an increase in the enzyme, as it increases energy expenditure and the need for the breakdown of glucose.

Many factors influence the results of the analysis, and they are not always a cause for concern and further examination:

Blood samples produce false positive results. Violation of the rules for storing samples and rough processing affect the accuracy.

With increased platelet count, serum LDH level also increases and does not show the real picture.

During hospitalization with suspected myocardial infarction and acute pancreatitis, LDH analysis is performed without taking into account the recommendations. Often, the LDH indicator is used to assess the dynamics of the disease and the patient’s recovery.

Norm of LDH in the body and interpretation of the analysis

When testing blood, the norm is usually indicated in units/l, which means one per liter. The interpretation of the analysis takes into account the age and gender of the patient. A relatively small amount of the enzyme is found in the blood of a healthy adult. In a child under two years of age, the norm is considered to be within 430 units/l.

An increase in lactate dehydrogenase occurs during pregnancy, in newborns, and in professional athletes.

Based on the identified marker, it is impossible to determine which cells were damaged. Therefore, when deciphering LDH, it is necessary to know what its isoenzymes are. Some laboratories conduct additional tests that determine several forms of the substance, starting with the most mobile:

The first indicates a problem with the heart, kidneys and red blood cells;

The second is found mainly in cardiomyocytes and erythrocytes;

The third is found in lung tissue, endocrine glands and adrenal glands;

the fourth is an enzyme in white blood cells, liver, placenta and male testicles and muscle tissue;

The fifth is found in all organs containing LDH-4, as well as skeletal muscles.

Deciphering biochemistry for increased LDH in the blood is now considered less informative.

High values ​​of all isoenzymes determine the pathology of several organs. Myocardial infarction with congestive heart failure causes lung damage and liver congestion. In cancer and autoimmune diseases such as lupus, lactate dehydrogenase is generally elevated. Hypoxia, shock and burns are accompanied by cell death, which shows an increase in LDH. Caffeine also affects the amount of enzyme in the blood.

The dynamics of the first isoenzyme are more sensitive and specific than the increase in LDH in general. Usually the level of the second isoenzyme is higher than the first. If the concentration of LDH-1 increases relative to LDH-2, a heart attack is diagnosed. Typically, the LDH level in the blood is exceeded 12-24 hours after damage to heart tissue and for two days in 80% of cases. A normal LDH-1/LDH-2 ratio is reliable evidence that there was no attack. The ratio of total LDH to LDH-1 is called hydroxybutyrate dehydrogenase. Therefore, during a heart attack:

The LDH/GBDG figure is reduced (less than 1.30);

The LDH-1/LDG-2 ratio approaches 1 and sometimes exceeds this value.

On the first day, myocardial infarction is diagnosed by the creatine kinase indicator, and a day later - by the enzymatic study of LDH. The activity of the substance is directly related to the area of ​​damage to the heart muscle.

Other serious diseases are reflected in the ratio of isoenzymes and coefficients:

Hemolytic anemia is characterized by a low LDH/GBDG figure - up to 1.3 and below;

In megaloblastic anemia, LDH-1 significantly exceeds LDH-2;

the general level increases during acute necrotic processes and cell death, such as damage to the kidney parenchyma;

tumors in the gonads (ovaries and testes) are accompanied by an isolated increase in LDH-1.

Most often, LDH is elevated due to the destruction of tissue of the liver and kidney parenchyma, and the death of platelets and red blood cells.

LDH in a blood test is considered in relation to other indicators:

With anemia, red blood cells are destroyed, which releases large amounts of LDH into the blood. The disease is diagnosed against the background of low hemoglobin. Weakness, pallor, shortness of breath may be indications for examination.

Blood cancer is associated with the production of abnormal blood cells, which is reflected in the levels of many indicators: LDH, aspartate aminotransferase, bilirubin, urea. At the same time, there is a decrease in the level of glucose and the blood clotting factor fibrinogen. A biochemical blood test allows one to suspect pathology and refer the patient to identify tumor markers.

Along with the LDH level in the blood, which indicates the death of pancreatic cells, bilirubin and glucose will increase. The primary indicator is the level of the pancreatic enzyme amylase.

Reasons for the increase

Elevated LDH levels can be caused by various diseases:

• stroke;
• some types of anemia (pernicious and hemolytic)
• kidney and liver diseases;
• muscular dystrophy;
• pancreatitis;
• Infectious mononucleosis;
• some forms of cancer.

The concentration of the enzyme increases after the administration of anesthetics and aspirin, as well as after intense physical exercise. Normal and reduced levels LDHs are not pathological. A factor that reduces the indicator is the consumption of a large dose of ascorbic acid (vitamin C).

The reasons that lactate dehydrogenase is elevated are varied: HIV infection, sepsis, acute diseases kidneys, infarction of the intestines and lungs, bone fractures, rash on the body.

LDH is reduced when transudate accumulates in body cavities, for example, in abdominal cavity, which is usually caused by congestive heart failure or cirrhosis.