: Lactate Dehydrogenase, Serum or Plasma

: What Is Lactate Dehydrogenase?

: Lactate dehydrogenase is an enzyme involved in energy production that is present in nearly all cells of the body, including the liver, heart, muscle, blood cells, and lungs. When cells are injured or break down, LDH leaks into the bloodstream, so a blood level can reflect ongoing tissue stress or damage.

: Why the Test Is Ordered

: A healthcare provider may order an LDH level to help evaluate unexplained tissue damage, monitor certain blood disorders, assess hemolysis (breakdown of red blood cells), or follow conditions affecting the liver, heart, or other organs. It is often used alongside other tests rather than on its own.

: How the Sample Is Collected

: The test is performed on a blood sample, typically drawn from a vein in your arm. The specimen may be processed as serum or plasma depending on the laboratory. No special preparation is usually required unless your provider gives other instructions.

: Understanding Your Results

: An LDH result is interpreted in the context of your symptoms, medical history, and other lab tests, because many different conditions can raise or, less commonly, lower the level. Your provider will explain what your specific result means for you; reference ranges vary by laboratory.