Also called: Lactic Acid Dehydrogenase Test, LD Test

Lactate Dehydrogenase (LDH) Blood Test

What Is a Lactate Dehydrogenase Blood Test and Why Is It Done?

A lactate dehydrogenase (LDH) blood test measures the amount of an enzyme, or a kind of protein, in the blood called LDH.

Doctors may order an LDH test to:

• screen for tissue damage that’s acute (from a traumatic injury) or chronic (from a long-term condition, like liver disease or some kinds of anemia)
• monitor progressive conditions (ones that get worse over time), like muscular dystrophy
• check some cancers, like lymphoma or leukemia, or how well chemotherapy is working

What Is Lactate Dehydrogenase (LDH)?

The enzyme LDH, also called lactic acid dehydrogenase, is in almost all body tissues. It helps the body turn glucose (sugar) from food into usable energy for our cells. When tissues are damaged, they release LDH, which can raise the level of the enzyme in the blood.

Top Things to Know

• The lactate dehydrogenase (LDH) blood test checks how much of the enzyme LDH is in the blood.
• The test can look for tissue damage, monitor certain conditions, and see how chemotherapy is working.
• Kids might need to stop exercising, taking certain medicines, or not eat or drink before the blood test.
• Your doctor can explain what it means if the LDH level is high or low.

How Can I Help My Child Prepare for a Blood Test?

To help kids get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is nervous about it, work together on ways to stay calm. Deep breathing or even imagining being in a place that makes your child feel safe and relaxed can help.

Certain things can increase the level of LDH, so tell your doctor if your child takes any medicines or vigorously exercises. Exercising should be avoided before a test.

And since lot of vitamin C could make the LDH level lower than normal, also avoid giving your child vitamin C before the test.

What Do Lactate Dehydrogenase Test Results Mean?

Your doctor will explain what the results of the test mean for your child. What’s “normal” can vary based on things like age and gender.

High Lactate Dehydrogenase Level

An elevated (high) LDH level could be due to:

• a problem with the liver, heart, or pancreas
• an infection like mononucleosis (mono)
• an injury to the muscles
• a broken bone

Low Lactate Dehydrogenase Level

It’s not common for LDH levels to be low. A lot of vitamin C could make the level look lower than normal, and some genetic conditions can cause the level to be lower than usual.

What Else Should I Know?

If your child has a high LDH level, your doctor may suggest having other blood tests (like an LDH isoenzymes test) to see where there might be tissue damage.

If you have questions about the LDH test or what the results mean, talk to your doctor.