Modern medicine does not stand still, and every day continues to develop. Many tests are used to diagnose various diseases. It is difficult for an ordinary person to understand all their names. Take, for example, LDH. What is this, not every inhabitant knows, but meanwhile, doctors use this research method quite often. What diseases can be diagnosed with the help of LDH analysis, which threatens its increased or decreased level in the blood. Let's get it right.
What is LDH?
First you need to understand what is hidden under the incomprehensible, at first glance, the acronym LDH. Lactate dehydrogenase is a special enzyme, without which glucose oxidation processes and the production of lactic acid are impossible. In the body of an adult, this substance is not able to accumulate. Thanks to 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 tissue or cells in the body are damaged. That is why LDH is a very important marker with which to diagnose.
Types of LDH
What is this, we have already figured out, however, it is necessary to clarify some features of this enzyme. As you know, it has five forms that differ from each other only in the structure of 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 - predominates in the tissues of the brain and heart muscles.
- LDH 2 - it contains blood cells (red blood cells, platelets) and the liver.
- LDH 3 - is found in the muscles of the skeleton, in the pancreas and thyroid glands, as well as in the tissues of organs such as the lungs, adrenal glands and spleen.
- LDH 4 - predominates in the same organs as LDH 3, and in addition, in the germ cells of men, the placenta, liver and granulocytes.
- LDH 5 - most of this isoenzyme is found in the tissues of skeletal muscles and liver, but, in addition, it is present in the same organs as LDH 4.
Norm
So, we figured out what LDH is. The norm of this enzyme is different in adults and babies, as well as in men and women. To begin with, what indicators are considered normal for children.
- On the first day of a child’s life, the concentration of the enzyme should be 22.1 µkat / l.
- The next four days, it rises to around 28.9.
- From a weekly age to six months, the level of LDH decreases. The norm is 16.3 μkat / l.
- Over the next 6 months of life, the level again increases slightly, this time to the level of 18.3.
- After the execution of one year and up to three years, LDH in children should be 14.2 μkat / l.
- From the age of seven, the indicators for different sexes begin to differ. For boys, the level should normally be 12.7 mkkat / l, and for girls - 9.67.
- After thirteen years, the enzyme index is at a stable level of 11.4 in boys and in adult men. In girls and women, this norm decreases slightly and throughout life is 7.27 mkkat / l.
LDH blood. What is it?
As already mentioned, this is an excellent marker for diagnosing various body problems. But what is a biochemical analysis of LDH? This is a blood test method that can be used to determine how much lactate dehydrogenase is in the blood. When does the need for such an analysis arise?
Indications for
LDH is performed when there is a suspicion that organs or their systems were injured. It is tissue damage that provokes an increase in the level of such an enzyme in the blood. This is especially true of the tissues of the heart, brain, lungs, kidneys, skeleton muscles.
If melanoma is suspected, blood LDH is also performed. What does it mean? The fact is that this analysis reveals metastases in organs and lymph nodes. This research method for melanoma cannot be called specific, but it allows you to control 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, therefore this marker is used to determine the dynamics of treatment.
Preparing for the test
Before conducting the analysis, 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 LDH results. What is it, we have already determined. However, what funds can not be taken three days before the analysis? These include: aspirin, anesthetics, ascorbic acid (vitamin C), mitromycin, clofibrate, procainamide, fluorides. You should also refrain from alcohol, as it is able to increase the level of the studied enzyme.
How is the analysis
Blood sampling in adults is carried out from a vein at the bend of the arm with a special needle. In order to take material from children or infants, use a lancet. In addition to a vein, a doctor can take blood from an earlobe, big toe, or heel. The place of the fence is processed, and after the procedure, a pressure bandage is applied to it. After the procedure, minor pain may occur.
Blood samples are placed in a test tube or on a glass slide. In the laboratory, the collected material is installed in a special centrifuge, with the help of which serum is extracted from it. Thus, the level of the enzyme in the blood is determined.
We have already talked about what the meanings should be. The amount of enzyme can be either increased or decreased. What can contribute to this?
Causes of High LDH
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 a tissue lesion has occurred. 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 refinement. Despite this, specialists need to know which organs to pay attention to first if LDH is elevated. The reasons may be as follows:
- Stroke.
- Myocardial infarction. In this case, the level may rise within 36–55 hours after the attack. An increased amount of the enzyme is maintained for 3-10 days.
- Lung infarction. Its first symptoms are pain in the chest area. Then the enzyme level rises.
- Intestinal infarction.
- Kidney infarction, pyelonephritis.
- Congestive heart failure.
- Liver pathologies also cause 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.
- Oncological diseases are also accompanied by an increase in LDH levels.
- Blood diseases provoke hemolysis.
- LDH is a marker in acute pancreatitis.
- Hypoxia, hypothermia, hyperthermia.
- Lymphoma
- Mononucleosis, which developed as a result of infection.
- Viral meningitis. An increase in LDH levels indicates that encephalitis is developing.
- Dystrophy, atrophy of muscles, their injuries.
- Traumatic shock.
- Cracks and bone fractures.
- Multiple burns.
- Convulsive seizures.
- Alcoholic or narcotic delirium.
- Eclampsia.
- For some pregnant women, elevated LDH levels are normal. For others, such analysis 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 studies are needed. 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 isoenzymes 4 and 5 of LDH was detected. What it is? Most likely, muscle or liver damage occurred. But to verify this, it is necessary to determine the functional tests of the diseased organ.
Thus, the result of LDH analysis can only be considered in conjunction with other studies. It is also important to monitor the dynamics of this process, since it plays an important role in determining pathological processes.
Low LDH
Sometimes test results may 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.
Low LDH levels are also possible with gene mutations. Perhaps only two of their species. People who are diagnosed with the first type will feel tired and muscle weak. Mutations of the second type have no symptoms. Excessive consumption of ascorbic acid (vitamin C) can also lead to a decrease in LDH levels.