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 your body. It can help identify conditions affecting cells, such as damage or disease.
["LDH helps diagnose conditions like heart attacks, muscle injuries, or certain cancers."]
Key facts at a glance
- LOINC
- 2541-1
- Short code
- LDH3 SerPl Chem Sepn-cCnc
- Synonyms
- LDH3 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 often checked alongside other tests to assess conditions like heart attacks (myocardial infarction), liver disease, red blood cell disorders, or muscle injuries. It can also be part of monitoring for certain cancers or infections.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The blood is processed to separate the serum or plasma, where the LDH enzyme activity is measured using a specialized lab test. The result is expressed in units per liter (U/L) or another standard unit.
What Does a High or Low LDH Level Mean?
Elevated LDH levels may suggest damage to cells, such as from a heart attack, liver disease, or certain cancers. Lower levels might be normal or could indicate conditions like anemia or certain genetic disorders, but this is less common. Your doctor will interpret results in the context of your overall health.
Common Conditions Linked to LDH Levels
High LDH is commonly seen in conditions like heart attacks, liver disease, muscle injuries, or blood cancers. Low LDH is less frequently abnormal and may require further evaluation by your healthcare provider.
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.
LDH is a useful marker for detecting or monitoring conditions that cause widespread cell damage. For example, it can help confirm a heart attack by detecting early changes in muscle cells. LDH may also be used to track the progression of certain cancers or infections, though it’s not always the sole test for these purposes. Your doctor will use LDH results alongside other tests and symptoms to guide diagnosis and treatment.
Short name
LDH Activity
Frequently asked questions
Why might my doctor order an LDH test?
What are 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 17, 2026. · Read our editorial policy