The lactate dehydrogenase test analyzes the body’s tissues for signs of deterioration or damage.

LDH is an enzyme needed to convert sugar into energy for your cells. The heart, liver, pancreas, kidneys, lymph tissue, skeletal muscles, and blood cells are just a few organs and tissues where LDH can be found.

When your cells are damaged by illness or injury, LDH is released into the bloodstream, causing your blood LDH level to rise. High levels of LDH in the blood indicate acute or chronic cell damage, but more testing is required to determine its origin. Furthermore, LDH levels that are abnormally low are uncommon and usually aren’t dangerous.

What Are The Different Types of LDH?

The term “isoenzyme” refers to the five different types of lactate dehydrogenase test. Minor structural differences characterise them. 

Different isoenzymes of LDH can be identified in various bodily tissues. The largest concentrations of each type of isoenzyme can be found in the following areas:

LDH-1: red blood cells and the heart

LDH-2: red blood cells and the heart

LDH-3: lungs, lymph tissue, platelets, and the pancreas

LDH-4: skeletal muscle and liver

LDH-5: skeletal muscle and liver

The most common uses for an LDH test are to:

  • Check to see if you have any tissue injury;
  • Monitor the progress of chemotherapy in patients who have cancer and show whether or not the treatment is effective; or
  • Keep an eye on any conditions that cause tissue injury: anemia, liver disease, lung diseases, and other types of infections.

What to expect during an LDH test:

A tiny needle is used to extract a blood sample from a vein in your arm by a healthcare provider, then a small amount of blood will be collected into a test tube or vial once the needle is inserted. When the syringe needle goes in or out, it may sting slightly. It usually takes less than five minutes to complete this procedure.

Other bodily fluids, such as those in the spinal cord, lungs, or abdomen, are sometimes tested for LDH. If you’re having one of these tests, your doctor will give you further advice about what to prepare.

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