Lactate Dehydrogenase (LDH) Activity in Serum
This test measures the activity of an enzyme called lactate dehydrogenase (LDH), which plays a role in energy production in cells. LDH levels can help identify conditions affecting cells, such as damage or disease.
["LDH helps doctors assess cell injury or disease in organs like the heart, liver, or muscles."]
Key facts at a glance
- LOINC
- 107736-1
- Short code
- Sheep Milk IgG Qn IA
- Synonyms
- Sheep Milk IgG Qn IA
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- CPT
- 82784
- 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
Why Is This Test Done?
Doctors may order LDH testing to investigate symptoms like chest pain, fatigue, or unexplained organ dysfunction. It can also be part of a broader evaluation for conditions such as heart attacks, liver disease, anemia, or certain cancers.
What Does the Test Measure?
LDH measures how much of this enzyme is present in your blood. Higher levels may suggest damaged or stressed cells releasing LDH into the bloodstream.
Common Conditions Linked to LDH Levels
Elevated LDH can signal conditions like heart attacks, liver disease, muscle injuries, red blood cell disorders, or certain cancers. Lower levels are less commonly significant unless part of a broader diagnostic workup.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for a few hours if your blood is drawn early in the morning. Wear a loose shirt for easy access to your arm.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: LDH in Diagnosis and Monitoring
Short name
LDH Serum
Frequently asked questions
Elevated LDH can indicate widespread cell damage, but it’s often used alongside other tests for a clearer picture. For example, high LDH with chest pain may raise suspicion for a heart attack, prompting further testing like an EKG or cardiac enzymes.
A high LDH level may prompt your doctor to investigate further, such as checking for conditions like liver disease, anemia, or infections. They may also order additional tests to pinpoint the cause.
No specific diet or medications are restricted for LDH testing. However, if you’re taking blood thinners or other medications, let your doctor know so they can consider this when interpreting results.
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