Lactate Dehydrogenase, Plasma or Serum, Catalytic Concentration
Lactate dehydrogenase (LDH) is an enzyme found in many tissues. This test measures how much LDH activity is present in a blood sample.
["LDH is a general marker of tissue activity and injury rather than a test for one specific organ."]
Key facts at a glance
- LOINC
- 60021-3
- Short code
- LDH Plr P to L-cCnc
- Synonyms
- LDH Plr P to L-cCnc
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- 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
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
What LDH Is
LDH is an enzyme that helps cells convert energy. It is present in many organs, including the liver, heart, muscle, red blood cells, and lungs. A blood LDH test measures the enzyme's catalytic activity in serum or plasma.
Why the Test Is Ordered
Your clinician may order LDH as part of a general health assessment, to help evaluate tissue injury or hemolysis, or to monitor certain conditions over time. It is usually interpreted alongside other tests and your symptoms.
How the Sample Is Collected
A blood sample is drawn from a vein, typically in your arm, and sent to the laboratory for analysis. No special preparation is usually needed unless your care team gives other instructions.
What Results Can Mean
An LDH result outside the expected range can occur with many different conditions, including liver, muscle, heart, or blood issues. Because it is not organ-specific, an abnormal result does not by itself diagnose a specific disease and is reviewed with other findings.
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.
Clinical significance: LDH elevations can reflect cell turnover or tissue damage from a variety of causes, including hemolysis, liver disease, muscle injury, and other disorders. Results are most useful when interpreted with the clinical picture and additional laboratory tests rather than in isolation.
Short name
LDH
Frequently asked questions
Does an abnormal LDH result always mean I have a serious condition?
Can I prepare for an LDH test?
Why might my doctor repeat an LDH 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 16, 2026. · Read our editorial policy