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Lactate Dehydrogenase (LDH) Activity in Serum

Published: August 9, 2026Updated: August 17, 2026

This test measures the activity of the enzyme lactate dehydrogenase (LDH), which helps assess cell damage or health in various tissues.

Quick summary

["LDH helps doctors check for conditions affecting muscle, liver, heart, or red blood cells."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
11053-6
Short code
LDH RBC-cCnc
Synonyms
LDH RBC-cCnc
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Matters

LDH is found in many body tissues, including the heart, liver, kidneys, and muscles. When cells are damaged, LDH levels can rise. This test can help identify issues like heart attacks, liver disease, anemia, or infections.

Common Conditions Monitored

Elevated LDH may signal conditions such as muscle injuries, certain cancers, or severe infections. Lower levels might suggest certain metabolic disorders or muscle wasting.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in the arm. The blood is then separated into serum (the liquid part after clotting) for testing. This test is typically done on fresh serum.

Testing Process

The LDH activity is measured using an automated laboratory method that detects how quickly a chemical reaction occurs in the serum sample, indicating enzyme activity levels.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

LDH is often used as a marker for tissue injury or disease. For example, high LDH levels can be associated with myocardial infarction (heart attack), liver disease, hemolytic anemia (red blood cell destruction), or certain cancers. It can also help monitor the progression of conditions like muscular dystrophy or monitor treatment responses in some cases.

Short name

LDH Serum

Frequently asked questions

What Does an Abnormal Result Mean?
An elevated LDH level may indicate tissue damage or disease, but it doesn’t always pinpoint the exact cause. Your healthcare provider will consider your symptoms, medical history, and other test results to determine the next steps.
Can LDH Levels Change Over Time?
Yes, LDH levels can fluctuate depending on the underlying condition. For example, after an injury or illness, levels may rise temporarily. Regular monitoring may be needed if you have a chronic condition affecting LDH.
Does Diet or Exercise Affect LDH Levels?
Exercise can temporarily increase LDH levels, especially in muscle-heavy activities. Certain foods or supplements may also influence enzyme activity, but diet alone rarely causes significant changes unless there’s a metabolic issue.
  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 17, 2026. · Read our editorial policy