Health Library

The Health Library is a collection of health and wellness resources created for learning and accessibility. Select a topic below for related health information or search for a topic in the search bar for more information on other medical conditions.

Spanish Translation

Top of the page

Lactate dehydrogenase (LDH)

Lactate dehydrogenase (LDH) is a protein (enzyme) that speeds up chemical reactions in the body. It is found in red blood cells and in many organs, including the heart, liver, muscles, lungs, brain, and kidneys.

There are five different fractions of LDH (called isoenzymes): LDH-1, LDH-2, LDH-3, LDH-4, and LDH-5.

A blood test to measure LDH levels is done to check for damage to organs throughout the body. The amounts of each isoenzyme also may be measured to help determine what organ may be damaged. Some conditions that increase LDH levels include stroke, heart attack, anemia, and hepatitis.

Current as of: May 1, 2026

Author: WebMD Ignite Staff

Clinical Review Board
All WebMD Ignite education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

This information does not replace the advice of a doctor. WebMD Ignite, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.