Lactate Dehydrogenase (LDH)

The Lactate Dehydrogenase (LDH) test measures the level of LDH enzyme in the blood. LDH is found in many tissues throughout the body, including the heart, liver, muscles, kidneys, lungs, and blood cells. Elevated LDH levels can indicate tissue damage, cell injury, or disease, and the test is often used to help diagnose or monitor various medical conditions.

1. What Is LDH?

• LDH (lactate dehydrogenase) is an enzyme involved in energy production, converting lactate to pyruvate and vice versa.

• It is released into the bloodstream when cells are damaged or destroyed.

• LDH levels are nonspecific but are helpful in identifying tissue damage or disease.

2. Why Is the LDH Test Performed?

This test is used to:

• Detect and monitor tissue damage or diseases affecting organs (e.g., heart, liver, muscles).

• Support diagnosis of hemolytic anemia or certain cancers.

• Monitor progression or response to treatment in conditions like lymphoma or leukemia.

• Evaluate inflammation, infection, or organ injury.

3. LDH Reference Range

• Normal range: 140 – 280 U/L (units per liter)

• Reference ranges may vary slightly depending on the laboratory.

4. Interpreting LDH Results

🔹 Elevated LDH:

• Suggests tissue damage or disease affecting the heart, liver, kidneys, muscles, lungs, or blood.

• Common causes include heart attack, liver disease, hemolysis, cancer, muscle injury, or infections.

🔹 Low LDH:

• Rare and generally not clinically significant.

• May occur due to large vitamin C intake or late-stage cancers affecting the liver.

5. What Can Affect LDH Levels?

• Recent injury or surgery

• Strenuous exercise or muscle trauma

• Hemolysis (breakdown of red blood cells)

• Liver or kidney disease

• Certain medications (e.g., anesthetics, aspirin, alcohol)

6. How Is the Test Performed?

• A blood sample is collected from a vein.

• Fasting is usually not required.

7. When to See a Doctor

🚨 Contact your healthcare provider if you:

• Have abnormal LDH results with symptoms of fatigue, pain, or unexplained illness.

• Are being monitored for cancer, anemia, or tissue damage.

• Require further evaluation of organ or cellular damage.

🔹 Key Takeaways

✅ LDH is a marker of tissue and cell damage, not specific to any one condition.

✅ Elevated levels may suggest organ injury, cancer, anemia, or infection.

✅ LDH is often used alongside other tests to guide diagnosis and monitor treatment.