Lactate Dehydrogenase (LDH) Activity in Serum/Plasma
This test measures the activity of the enzyme lactate dehydrogenase (LDH), which plays a key role in energy production in cells. It helps assess conditions affecting cell damage or metabolism.
["LDH helps diagnose and monitor conditions linked to tissue injury or metabolic dysfunction."]
Key facts at a glance
- LOINC
- 2543-7
- Short code
- LDH3 SerPl-cCnc
- Synonyms
- LDH3 SerPl-cCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 140
- Ref high
- 280
- Critical range
- — – 1000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 83615
- 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
Why Is This Test Done?
Doctors may order LDH testing to evaluate symptoms like fatigue, muscle pain, or unexplained lab abnormalities. It’s often used alongside other tests to identify conditions such as heart attacks, liver disease, muscle disorders, or certain cancers.
What Does a Result Mean?
Results are not given in absolute numbers here since reference ranges vary by lab. Instead, they’re compared to your baseline or other tests to identify patterns. Elevated LDH may suggest cell damage, while lower levels could indicate certain metabolic or genetic conditions.
Common Conditions Monitored
LDH is commonly checked in cases of suspected myocardial infarction (heart attack), liver disease (e.g., hepatitis), muscle disorders (e.g., myositis), or hematologic conditions (e.g., anemia, leukemia). It can also be part of routine cancer screenings.
Sample Collection and Preparation
A blood sample is drawn from a vein, typically in the arm. The blood is processed to separate serum or plasma for testing. Avoid strenuous activity or eating heavy meals before your test, as these may affect results.
Reference range
Adult: 140-280 U/LN/A
No special preparation required. Inform provider of any chest pain or symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
LDH Activity
Frequently asked questions
What factors might influence my LDH test results?
How soon will I get my results?
Can I fast before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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