: Lactate Dehydrogenase Panel, Serum or Plasma

: What Is Lactate Dehydrogenase?

: Lactate dehydrogenase (LDH) is an enzyme present in nearly every cell of the body, including the liver, heart, muscles, kidneys, and red blood cells. When cells are damaged or destroyed, LDH leaks into the bloodstream, so measuring its level gives a broad view of tissue health rather than pinpointing one specific organ.

: Why the Test Is Ordered

: A healthcare provider may order an LDH panel to investigate unexplained fatigue, fever, or weight loss, to help evaluate suspected tissue injury or certain blood disorders, or to monitor a condition over time. Because LDH is not specific to any one organ, it is usually part of a larger set of tests.

: How the Sample Is Collected

: The test requires a blood draw, typically from a vein in the arm. The sample is collected in a tube and the laboratory measures LDH activity in the serum or plasma portion. Your provider will let you know whether fasting or other preparation is needed.

: What the Results Mean

: An LDH result outside the typical range can occur for many reasons, including tissue injury, hemolysis (breakdown of red blood cells), liver or muscle conditions, or other illnesses. A single value is not diagnostic; your provider interprets it together with your symptoms, physical exam, and other laboratory findings. Reference ranges vary by laboratory, so results should be read in the context of the reporting lab.