Lactate Dehydrogenase (LDH) Activity in Serum/Plasma
This test measures the activity of the enzyme lactate dehydrogenase (LDH), which plays a role in energy production in cells. It helps assess conditions affecting cell damage or function.
["LDH helps doctors identify potential issues like heart damage, muscle injury, or certain cancers."]
Key facts at a glance
- LOINC
- 60017-1
- Short code
- LDH Fld P to L-cCnc
- Synonyms
- LDH Fld P to L-cCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- reaction-pyruvate-to-lactate
- CPT
- 85610
- SNOMED
- 396252006
- 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 Does LDH Measure?
LDH is an enzyme found in many tissues throughout the body. When cells are damaged—such as due to injury, infection, or disease—their contents, including LDH, can leak into the bloodstream. Measuring LDH helps evaluate how widespread or severe the damage might be.
Common Uses of LDH Testing
Doctors may order LDH tests to investigate symptoms like chest pain, muscle weakness, or unexplained fatigue. It’s also used in diagnosing conditions such as heart attacks, liver disease, red blood cell disorders, or certain types of cancer.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The blood is then sent to a lab, where LDH activity is measured using an enzymatic method. Results are typically available within 24 hours.
What Might Elevated LDH Levels Indicate?
Higher-than-normal LDH levels may suggest conditions causing cell damage, such as heart attacks, muscle injuries, infections, or certain cancers. However, LDH alone isn’t diagnostic—it’s often used alongside other tests for a full picture.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
LDH Test
Frequently asked questions
Why might my LDH test be ordered?
What are the typical reference ranges for LDH?
Can lifestyle changes affect LDH levels?
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 16, 2026. · Read our editorial policy