Lactate Dehydrogenase (LDH) Test

The human body needs energy as fuel to complete its day-to-day tasks. The fuel is produced by proteins called enzymes. And these enzymes are often present in every cell of your body. Sometimes they’re more than you may need and vice versa.

There are different types of enzymes present in the body of a human, but one of the most important is LD or LDH (Lactate Dehydrogenase). This enzyme is part of the energy production for every cell of the body, mainly in the heart, lungs, kidney and muscles and in the blood cells.

The LDH test is recommended by the doctor to measure the amount of LDH enzyme present in fluids, such as blood and others. When the cells present in the human body are damaged or destroyed, the enzyme LDH is released in the fluid portion of the body, i.e., the blood.

The amount of LDH present in the blood is very low compared to the cells of the human body. The results of the LDH test, however, reveal that it is considered to be a very non-specific marker to measure the presence of the damaged tissue in the organism. Many studies conclusion, elevated serum levels of lactate dehydrogenase (LDH) are indicative of cytokine-mediated tissue damage and release of LDH, which is a predictor of poor outcomes.

The LDH test result is often considered so inaccurate that by itself, it cannot be trusted to identify the location or cause of the cellular damage. But that’s not all there is to the LDH test; it is often used in conjunction with other blood tests to monitor or evaluate severe diseases of the heart and brain, especially the kind of tissue damage that leads to cancer.

In conditions like injury, inflammation or infection around a certain region of the body, like the brain, heart and lungs, the fluid version of LDH is accumulated or its constituents are usually changed. The result of the LDH test will reveal the levels of LDH present in the body as a form of fluid, which in-turns help the doctors to determine the cause of tissue damage.

The LDH enzymes are typically high in cerebrospinal fluid (liquid produced in the brain that surrounds the brain and the spinal cord) when the human has bacterial meningitis(Spinal Meningitis). The LDH test results, when combined with tests, can be useful in determining the cause of damaged tissues around cells, such as the heart, brain and lungs. Serum LDH was validated for its potential usefulness as a marker for evaluating clinical severity and monitoring treatment response in COVID-19 pneumonia.

A blood sample will be drawn from the veins of your forearms. In the case of cerebrospinal fluid, a sample is collected by lumbar puncture (a thin needle is inserted in your lower back).

Clinical severity and monitoring treatment response in COVID-19 pneumonia, Management of cancer therapy, Monitoring various injury, inflammation and infection severity

The necessity of the LDH test in COVID is undeniable in a word and this is the reason why a large number of doctors are suggesting to go for the test. As we all know, this test can help the experts determine the presence of tissue damage. On the other hand, it can help in predicting acute respiratory distress syndrome in those patients who have been affected by SARS-COV-2. In other words, it can be passively considered as one of those tests that can help you determine the presence of the deadly respiratory disease in you and this is why the test is necessary in COVID.

Also, routinely the consulting doctor that you are seeing may ask you to take the LDH test for a varied number of reasons. The most common ones are:

• To evaluate and monitor severe infections.
• To monitor conditions like hemolytic and megaloblastic anaemias.
• To monitor kidney diseases.
• To monitor lung diseases, especially ARDS.
• To evaluate certain cancers in your body like CLL.
• To evaluate the treatment of cancer.
• To monitor the severity of COVID-19 infection.

Your doctor may order you to have an LDH test of body fluids to:

• To find the reason for fluid build-up.
• To learn if you have bacterial meningitis.

Note: In conditions like cancer and treatment of cancer, you may have to be regularly tested for LDH.

The LDH test is usually done in conjunction with the other tests to determine the level of tissue damage in the cells of the human body. One should get this test done only when recommended by the doctor.
In case you are suffering from cancer or COVID-19 infection, LDH tests become a part of your diagnosis and treatment. So, you may then need to get tested more often

Before the Test

Generally, no special test preparation is required before an LDH test. However, if this test is done in conjunction with another test, your physician may ask you to avoid certain food items. In order to get the most accurate results, it is necessary to consult a medical professional before taking the test.

During the Test

A phlebotomist will draw blood from a vein in your arm to collect a sample. Your experience will be something like this:

• The area where the needle will be inserted is cleaned with antiseptic lotion.

• A tourniquet band is tied around the arm to dilate the veins.

• A new syringe needle will be inserted into the vein to draw blood. This procedure may take a few seconds, during which you may feel a slight pain of needle pricking.

• Your blood sample will be stored in a small vial or test tube with your test details.

After the Test

Once the blood is collected:

• A sticking plaster is applied to the needle insertion site to prevent bleeding.

• There may be a slight soreness or lightheadedness in some cases, nothing to worry about. You may be asked to sit for a few minutes.

• Contact your doctor if there is bleeding, pain or rashes at the puncture site.

The LDH test includes the following parameters:

• Measurement of tissue damage.
• Monitoring and evaluation of severe lung, brain and heart diseases.
• Monitoring infections.
• Monitoring chemotherapy for cancers.
• Evaluation of cancer treatment.
• Management of COVID-19 infection.

The levels of LDH may differ in males and females, but this is known as the formal normal range for the LDH test results.

The normal values and reference ranges of the test may vary from lab to lab. Please refer to the ranges mentioned in the report and consult a doctor to understand the interpretation of lab reports.

The LDH test is typically in conjunction with other tests to get accurate results of the damaged or destroyed tissues.

The higher levels of LDH shown in the results may mean you might have some level of tissue damage.

An LDH test can have varying costs depending on the city and the laboratory. Typically, the price for an LDH test falls between INR 299 and INR 825. Here's a breakdown of the average expenses for an LDH test in select major cities in India: