What is LDH? What does high and low LDH mean?

By | 17 May 2021

Lactate dehydrogenase, abbreviated as LDH, is a type of enzyme that can be detected in almost any cell in the body and is used to extract energy from sugar. Lactate dehydrogenase, which is found in high amounts in liver, lung, and muscle tissues, especially in the heart, is found in many tissues and organs of the body. The Lactate dehydrogenase enzyme, also known as lactate dehydrogenase or LD, enters the blood when cell, tissue, or organ damage occurs. By measuring the LDH enzyme, which is normally present in a small amount in the blood, in the laboratory environment, the location of the tissue damage in the body and whether the existing damage is progressing can be understood. LDH, a biochemical test, is performed with a blood sample taken from a vein in the arm. Since no prior preparation is required for the test, the amount of lactate dehydrogenase (LDH) enzyme in the bloodstream is quickly measured. If there is cell damage or destruction, tissue damage in the body, the Lactate dehydrogenase enzyme found in tissues and cells enters the blood and the level of LDH in the blood rises. If an elevation of it is detected in the laboratory test, the presence of damaged tissue in the body is suspected. The lactate dehydrogenase test is also done to understand how the body responds to a treatment against some diseases. Before moving on to the causes of high Lactate dehydrogenase  and low Lactate dehydrogenase, “What is Lactate dehydrogenase?” Must answer the question.

What is LDH?

Lactate dehydrogenase (LDH) is an enzyme found in almost every cell and tissue in the body. The main purpose of this enzyme is to obtain energy from sugar in the body. Lactate dehydrogenase enzyme, which is found in high amounts in the heart, liver, lungs, and muscles, is used in the investigation of many diseases and some blood diseases. Due to its high content in the organs and tissues listed above, it is a frequently used test in clinical applications to investigate diseases present in these organs. The height of total activity in the LDH enzyme indicates the presence of tissue damage or cell destruction in the body. This is because large amounts of Lactate dehydrogenase enzymes released from cells enter the blood during damage or destruction. This situation may occur in healthy pregnancies, after vigorous exercise, and in the presence of many discomforts, and may cause increased lactate dehydrogenase. “What does Lactate dehydrogenase mean?” The question can be answered in this way. Lactate dehydrogenase enzyme elevation is measured as total Lactate dehydrogenase or LDH isoenzymes. Total Lactate dehydrogenase measurement is the measurement of all five different lactate dehydrogenase enzymes. It is important to evaluate LDH enzymes separately as they are found in high amounts in different tissues of the body, which are different molecular variations of LDH-1, 2, 3, 4, and 5. In other words, with the measurement of total LDH, the disease that causes cell damage and the organs and tissues affected by this situation can be understood. The different lactate dehydrogenase enzymes and their high concentration are listed below:

  • LDH-1 (4H): It is found in high amounts in the heart and kidneys. If this value is high, it gives information about the presence of the disease that causes cell damage in the relevant regions.
  • LDH-2 (3H1M): It is found in high concentrations in erythrocytes known as red blood cells. If this value is high, it indicates the presence of damage or destruction in blood cells.
  • LDH-3 (2H2M): It is a molecular enzyme found in high amounts in the lungs. It is an indication of the problem in the lung tissues.
  • LDH-4 (1H3M): It is an indicator of destruction or damage in leukocytes, also known as kidneys, lymph nodes, and white blood cells (WBC).
  • LDH-5 (4M): It is found in high amounts in liver and muscle tissues. If this value is high, it indicates the presence of disease in the relevant tissues.

What does high LDH mean?

Measurement of LDH enzyme level is made in a laboratory environment with a blood sample taken from the arm. LDH height means getting results above the reference values ​​determined for the test. A small elevation in lactate dehydrogenase usually does not indicate any health problems. This situation can occur after sports and heavy exercises, as well as when exposed to cold. In the total LDH test, the elevation in different LDH isozymes can be a harbinger of a disease, or it can be seen as a result of cell and tissue damage. The causes of high LDH, or in other words, some of the conditions that lead to high LDH are listed below:

  • Some types of cancer, such as testicular and lymphoma cancer
  • Diseases such as stroke and CVA that develop due to problems in the cerebral vessels
  • Encephalitis
  • Liver diseases
  • Kidney diseases
  • Heart diseases
  • Pulmonary embolism
  • Muscular dystrophy
  • Pancreatitis
  • Hemolytic anemias
  • Pernicious anemia
  • Kiss sickness
  • Meningitis
  • Ischemia
  • Pneumonia
  • Bone fractures
  • Muscle injuries
  • Low blood pressure
  • Infections
  • Some chronic diseases
  • Use of certain types of drugs

What does low LDH mean?

If the LDH level is below the reference values ​​as a result of the test, it is defined as low Lactate dehydrogenase. Although low Lactate dehydrogenase is not a common condition, it is not considered as the presence of a problem on its own. Excessive vitamin C intake is among the factors that cause low Lactate dehydrogenase levels. Genetic predisposition can also cause low LDH levels. Those with low lactate dehydrogenase levels often feel tired during physical activities that require a high pace. Muscle stiffness, cramping, and muscle pain are common symptoms associated with low LDH.

What are normal LDH values?

Lactate dehydrogenase, which is always present in the blood, is measured with a biochemical test in a laboratory environment with a blood sample taken from the person’s arm. LDH value varies according to age and gender. Lactate dehydrogenase reference values ​​or in other words normal LDH values ​​are below:

  • 0-1 month: 225-600 U / L
  • 1-12 months: 100-400 U / L
  • 1-3 years: 100-300 U / L
  • 4-18 years: 100-250 U / L
  • Adult Female: 90 to 220 U / L
  • Adult Male: 90 to 240 U / L

Why is the LDH test done?

Lactate dehydrogenase, which is found in almost every cell and tissue of the body, is a type of enzyme used to obtain energy from sugar. Lactate dehydrogenase, which is always present in the blood, in case of cell damage, destruction, or tissue damage, enters the blood and causes an increase in Lactate dehydrogenase in the blood. This increase is detected in the laboratory environment thanks to the Lactate dehydrogenase test performed by looking at the blood. Each isoenzyme of LDH, which has five different variations, can be measured separately. With this measurement made with the total LDH test, diseases and injuries in different tissues can be detected. This is because different Lactate dehydrogenase isoenzymes are found in different concentrations in different organs. For example, an increase in Lactate dehydrogenase-1, which is concentrated in the heart and kidneys, indicates a disease present in these organs, while LDH-5 is found in excess in the liver and muscle tissues. Therefore, the increase in LDH-5 level is associated with existing disease or damage in liver and muscle tissues. The test, which is carried out to obtain information about the presence and severity of acute or chronic tissue damage, is also performed to monitor progressive diseases in some cases. Lactate dehydrogenase testing is usually needed when the physician suspects cell and tissue damage. According to the results of the test, if the LDH level is above normal values, the physician may request additional tests to investigate which organs are affected. The physician may sometimes request a Lactate dehydrogenase test to follow up on the damage caused by muscle trauma or injuries. While high Lactate dehydrogenase is seen due to many different diseases, low Lactate dehydrogenase mostly occurs due to high vitamin C intake.

For a healthy life, do not neglect to have your health checks regularly.



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