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 metabolism.
["LDH helps identify tissue damage or metabolic issues by measuring enzyme activity in your blood."]
Key facts at a glance
- LOINC
- 2544-5
- Short code
- LDH4 SerPl Chem Sepn-cCnc
- Synonyms
- LDH4 SerPl Chem Sepn-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
- Method
- chemical-separation
- 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
What Is LDH Used For?
LDH is commonly used to diagnose or monitor conditions such as heart attacks, muscle injuries, liver disease, red blood cell disorders, and certain cancers. Elevated levels may suggest widespread tissue damage, while lower levels could indicate certain metabolic or genetic conditions.
How Is the Test Performed?
A blood sample is drawn from a vein in your arm. The serum or plasma is then tested for LDH activity using a specialized laboratory method, often enzymatic, to measure how quickly it converts lactate to pyruvate.
What Does a Result Mean?
Results are not provided with specific reference ranges, as they vary by lab and condition. Your healthcare provider will interpret the result in relation to your symptoms, medical history, and other test results.
Common Conditions Affecting LDH Levels
Elevated LDH levels may be linked to conditions like myocardial infarction (heart attack), muscle injuries (e.g., rhabdomyolysis), liver disease, hemolytic anemia (red blood cell breakdown), or certain cancers. Lower levels may be seen in rare metabolic disorders or during certain medications.
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.
Clinical Significance
Short name
LDH Activity
Frequently asked questions
Why might my doctor order this test?
How soon will I get my results?
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 17, 2026. · Read our editorial policy