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
- 51521-3
- Short code
- LDH5 CFr Plr Elph
- Synonyms
- LDH5 CFr Plr Elph
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Ref low
- 140
- Ref high
- 280
- Critical range
- 7.2 N/A – 7.6 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- electrophoresis
- CPT
- 83615
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
What Is LDH Used For?
LDH is commonly used to detect and monitor conditions that cause cell damage, such as heart attacks, muscle injuries, liver disease, or certain cancers. It can also help evaluate red blood cell disorders or metabolic disorders.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The sample is sent to a lab where LDH activity is measured using an enzymatic method. Results are reported in units per liter (U/L) or other standardized units.
When Might You Need This Test?
Your healthcare provider may order an LDH test if you have symptoms like chest pain, muscle weakness, fatigue, or unexplained bruising. It’s also used in follow-up for known conditions like heart disease, liver problems, or cancer.
What Do Results Mean?
Elevated LDH levels may suggest damage to cells in organs like the heart, liver, or muscles. Lower levels might indicate certain metabolic or genetic conditions. Your results will be interpreted in relation to your symptoms and medical history.
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: LDH is a sensitive marker for tissue injury across multiple organ systems. While not specific to a single condition, elevated levels often prompt further investigation into potential causes like myocardial infarction, hemolysis, or malignancy.
Short name
LDH Activity
Frequently asked questions
Why was this test ordered for me?
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 16, 2026. · Read our editorial policy