Skip to content

Lactate Dehydrogenase (LDH) Activity in Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the activity of the enzyme lactate dehydrogenase (LDH), which plays a role in energy production in cells. It helps assess damage to cells, including those in the heart, liver, kidneys, and red blood cells.

Quick summary

["LDH helps identify tissue injury or metabolic conditions by measuring enzyme levels in your blood."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
48581-3
Short code
LH D11 SerPl-aCnc
Synonyms
LH D11 SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
1.5
Ref high
9
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
83002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is LDH Used For?

LDH is often used to diagnose or monitor conditions affecting multiple organs. Elevated levels may suggest damage to cells in the heart, liver, lungs, kidneys, or red blood cells. It can also help evaluate certain cancers or infections.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum or plasma, where the LDH enzyme activity is measured using a specialized laboratory test.

What Might Influence Results?

Several factors can affect LDH levels, including recent exercise, certain medications, infections, or underlying health conditions. If you have recent trauma, surgery, or a known condition like heart disease or cancer, your doctor may request this test.

When Might You Need This Test?

Your doctor may order an LDH test if you have symptoms like chest pain, unexplained fatigue, jaundice, or if they suspect conditions like heart attack, liver disease, anemia, or certain cancers.

Reference range

Follicular: 1.5-9.0 mIU/mLN/A

Specimen: serum

For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

LDH Activity

Frequently asked questions

Why is LDH important in diagnosing conditions?
LDH is important because it can help determine the extent of tissue damage across different organs. For example, elevated LDH may indicate muscle injury, but higher levels in specific patterns can point to heart damage (e.g., myocardial infarction) or liver disease. It’s also used as a marker in some cancers to track progression or response to treatment.
How do LDH levels change with certain diseases?
In diseases like heart attacks, LDH levels often rise within hours and peak in a few days. In liver diseases, elevated LDH may appear alongside other liver function tests. In conditions like anemia or infections, LDH can also be elevated due to red blood cell breakdown.
Can LDH levels be misleading?
Yes, LDH levels can be influenced by factors like recent exercise, certain medications, or dehydration. If your results are abnormal, your doctor will consider these factors and may order additional tests to get a clearer picture.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy