Lactate Dehydrogenase (LDH)

What is Lactate Dehydrogenase?

Lactate dehydrogenase (LDH) is an enzyme found in nearly all body tissues, including heart, liver, kidneys, skeletal muscle, brain, and red blood cells. It helps convert lactate to pyruvate in cellular energy production. When tissues are damaged, LDH releases into the bloodstream.

Why is it Tested?

Doctors order LDH to detect tissue damage, monitor certain cancers, evaluate anemia, or investigate unexplained symptoms. It’s a general marker of cellular damage but requires additional tests to determine the specific source, as LDH can be elevated by many different conditions.

Normal Ranges

Reference ranges vary by lab:

Adults: 140–280 U/L

LDH levels can vary with age, with slightly higher values sometimes seen in older adults. The normal range is relatively wide due to the enzyme’s presence in multiple tissues.

Reference ranges vary by authority. Track yours across multiple standards with automatic unit conversions in LabsVault.

What do Abnormal Results Mean?

Abnormal results are not a diagnosis. Always discuss your results with a qualified healthcare provider before making any medical decisions.

High LDH

Elevated levels may indicate:

Heart attack or heart muscle damage
Liver disease or hepatitis
Hemolytic anemia (red blood cell destruction)
Certain cancers (lymphoma, leukemia)
Muscle injury or disease

Low LDH

Lower levels are less common but may suggest:

Genetic LDH deficiency
Advanced liver disease
Certain medications affecting enzyme function

How to Track Over Time

LDH trends help monitor disease progression and treatment response, particularly in cancer care and hemolytic conditions. Since LDH is nonspecific, tracking alongside other markers provides better insight into the underlying condition and treatment effectiveness.

Lactate Dehydrogenase