Lactate Dehydrogenase (LDH) Activity in Serum/Plasma (24-Hour Rate)
This test measures the activity of the enzyme lactate dehydrogenase (LDH) over a 24-hour period in your blood. LDH helps convert lactate to pyruvate and is found in many tissues, including the heart, liver, and muscles.
["LDH activity can help identify tissue damage or metabolic processes over time in your blood."]
Key facts at a glance
- LOINC
- 47863-6
- Short code
- LDH 24h Ur-cRate
- Synonyms
- LDH 24h Ur-cRate
- Category
- chemistry
- Sample
- urine
- Container
- Sterile urine container
- 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
- CPT
- 83615
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Doctors may order this test to assess conditions affecting multiple organs, such as heart disease, liver problems, muscle injuries, or certain cancers. It can also help monitor metabolic health or response to treatments.
What Does It Measure?
The test measures the rate at which LDH converts lactate to pyruvate in your blood over 24 hours. Elevated or decreased rates may signal underlying issues like tissue damage, infections, or metabolic disorders.
Sample Collection and Preparation
A blood sample is drawn from a vein, typically in the arm. The sample is processed to separate serum or plasma, which is then analyzed for LDH activity. The 24-hour rate accounts for metabolic fluctuations over time.
Common Conditions Monitored
High LDH rates may indicate conditions like heart attacks, liver disease, muscle injuries, or certain cancers. Low rates could suggest metabolic imbalances or rare genetic disorders.
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 of LDH activity involves evaluating tissue integrity, metabolic function, and disease progression. Elevated LDH is often associated with cell damage or increased lactate production, while low levels may reflect reduced enzyme activity or specific metabolic states.
Short name
LDH Rate (Serum/Plasma, 24h)
Frequently asked questions
What does a high LDH rate mean?
What does a low LDH rate mean?
How often is this test repeated?
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