Modern medicine does not stand still, but continues to develop every day. Many tests are used to diagnose various diseases. It can be difficult for an ordinary person to understand all their names. Take, for example, LDH. What it is, not every layman knows, but meanwhile doctors use this research method quite often. What diseases can be diagnosed using the analysis of LDH, what threatens its increased or decreased level in the blood. Let's figure it out.
What is LDH
First you need to figure out what is hidden under the incomprehensible, at first glance, abbreviation LDH. Lactate dehydrogenase is a special enzyme, without which the processes of glucose oxidation and the production of lactic acid are impossible. In the body of an adult, this substance is not able to accumulate. Through natural processes, it is destroyed and excreted. However, there are some diseases that are characterized by elevated levels of LDH in the blood. This occurs when tissues or cells of the body are damaged. That is why LDH is a very important diagnostic marker.
LDH types
What is it, we have already figured out, but some features of this enzyme need to be clarified. As you know, it has five forms, which differ from each other only in the structure of the cells. In addition, each of these types is concentrated in separate organs.
Modifications of the LDH enzyme are called isoenzymes. So, they distinguish:
- LDH 1 - predominant in the tissues of the brain and heart muscles.
- LDH 2 - it contains blood cells (erythrocytes, platelets) and liver.
- LDH 3 - found in skeletal muscles, pancreas and thyroid glands, as well as in the tissues of organs such as the lungs, adrenal glands and spleen.
- LDH 4 - prevails in the same organs as LDH 3, and in addition, in male germ cells, placenta, liver and granulocytes.
- LDH 5 - most of this isoenzyme is found in the tissues of skeletal muscles and the liver, but, in addition, it is present in the same organs as LDH 4.
Norma
So we figured out what LDH is. The rate of this enzyme is different in adults and babies, as well as in men and women. Let's start with what indicators are considered normal for children.
- On the first day of a child's life, the concentration of the enzyme should be22, 1 mkat/l.
- The next four days it increases to 28, 9.
- From a week of age to six months, the level of LDH decreases. The norm is 16.3 mkat/l.
- The next 6 months of life, the level increases slightly again, this time to 18, 3.
- After the age of one year and up to three years, LDH in children should be 14.2 mkat/L.
- From the age of seven, the indicators for different sexes begin to differ. For boys, the normal level should be 12.7 mkat / l, and for girls - 9.67.
- After the age of thirteen, the enzyme is at a stable level of 11.4 in boys and in adult men. In girls and women, this rate is somewhat reduced and throughout life is 7.27 mkat / l.
blood LDH. What is this?
As already mentioned, this is an excellent marker for diagnosing various problems of the body. But what is a biochemical analysis of LDH? This is a blood test that can be used to determine how much lactate dehydrogenase is in the blood. When does such an analysis become necessary?
Indications for conduction
LDG is carried out when there is a suspicion that organs or their systems have been injured. It is tissue damage that provokes an increase in the level of such an enzyme in the blood. This is especially true for the tissues of the heart, brain, lungs, kidneys, skeletal muscles.
If melanoma is suspected, blood LDH is also carried out. What does it mean? The point is that this analysisidentify metastases in organs and lymph nodes. This research method for melanoma cannot be called specific, but it allows you to monitor the patient's condition in the postoperative period, as well as determine the stage of tumor development. In addition, in the case of effective therapy, the level of the enzyme in the blood decreases, so this marker is used to determine the dynamics of treatment.
Preparing for the test
Before testing, the patient must prepare for it. Most likely, the doctor will advise you to refrain from taking certain medications, as they can affect the accuracy of the LDH results. What it is, we have already determined. However, what funds should not be taken three days before the analysis? These include: aspirin, anesthetics, ascorbic acid (vitamin C), mithromycin, clofibrate, procainamide, fluorides. You should also refrain from alcohol, as it can increase the level of the studied enzyme.
How the analysis is done
Blood sampling in adults is carried out from a vein at the bend of the arm using a special needle. In order to take material from children or infants, a lancet is used. In addition to a vein, the doctor may take blood from the earlobe, big toe, or heel. The site of the fence is processed, and after the procedure, a pressure bandage is applied to it. There may be slight pain after the procedure.
Blood samples are placed in a test tube or on a glass slide. In the laboratory, the collected material is placed in a specialcentrifuge, with the help of which serum is separated from it. Thus, the level of the enzyme in the blood is determined.
We have already talked about what the values should be. The amount of enzyme can be either increased or decreased. What can contribute to this?
Causes of elevated LDH levels
If the test results indicate an increase in LDH, it is necessary to look for the cause of this phenomenon. Its high level indicates that some tissue has been damaged. If the results show an increase in the amount of not one isoenzyme, but several, this may indicate that there are a number of disorders in the body. It happens that the test results indicate an increase in the level of all five types of LDH. In this case, we can talk about multiple organ failure.
However, the diagnosis cannot be made based solely on the level of LDH. A blood test for a change in the number of isoenzymes helps, rather, in its clarification. Despite this, specialists need to know which organs to pay attention to first of all if LDH is elevated. The reasons may be as follows:
- Stroke.
- Myocardial infarction. In this case, the level may rise for 36-55 hours after the attack. An increased amount of enzyme is maintained for 3-10 days.
- Lung infarction. Its first symptoms are pain in the chest area. At the same time, the level of the enzyme rises.
- Intestinal infarction.
- Kidney infarction, pyelonephritis.
- Congestive heart failure.
- Liver pathologies are also becomingcause of elevated LDH levels. What does it mean? First of all, the amount of this enzyme increases with cirrhosis, tissue changes due to alcoholism, as well as acute viral hepatitis.
- Cancer is also accompanied by an increase in LDH levels.
- Blood diseases provoke hemolysis.
- LDH is also a marker for acute pancreatitis.
- Hypoxia, hypothermia, hyperthermia.
- Lymphoma.
- Mononucleosis due to infection.
- Viral meningitis. An increase in LDH levels indicates that encephalitis is developing.
- Dystrophy, muscle atrophy, their injuries.
- Traumatic shock.
- Cracks and fractures of bones.
- Multiple burns.
- Convulsive seizures.
- Alcoholic or drug delirium.
- Eclampsia.
- For some pregnant women, elevated LDH levels are normal. For others, such test results may indicate placental abruption. In any case, an increase in LDH is a reason to see a doctor.
As already mentioned, an elevated level of one or more LDH isoenzymes cannot in itself indicate one of the above diseases. Other research needs to be done. Be sure to determine the activity of a particular isoenzyme. Then it will be possible to talk about the localization of the problem.
For example, a high level of LDH isoenzymes 4 and 5 was detected. What it is?Most likely, there was damage to the muscle tissue or liver. But to be convinced of this, it is necessary to determine the functional samples of the diseased organ.
Thus, the result of LDH analysis can only be considered in conjunction with other studies. It is also important to follow the dynamics of this process, since it plays an important role in determining pathological processes.
Low LDH
Sometimes test results can show a decrease in LDH levels in the blood. This is a rather rare case, which indicates that the body breaks down glucose very actively and receives energy from it for cells, mainly muscle cells.
Decreased LDH levels are also possible with gene mutations. Perhaps there are only two types. People who are diagnosed with the first type will feel tired and have muscle weakness. Mutations of the second kind do not have any symptoms. Excessive consumption of ascorbic acid (vitamin C) can also lead to a decrease in LDH levels.
