Serum Lactate Dehydrogenase (LDH) Macroassay
This test measures the total activity of lactate dehydrogenase, an enzyme found in many tissues, including the heart, liver, and muscles. It helps assess cell damage or disease processes.
["LDH helps detect conditions affecting cells across the body, often linked to organ damage or inflammation."]
Key facts at a glance
- LOINC
- 100742-6
- Short code
- LDH Macro SerPl Ql
- Synonyms
- LDH Macro SerPl Ql
- 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
- 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
Why Is This Test Done?
Doctors may order an LDH test to investigate symptoms like fatigue, chest pain, or unexplained bruising, which could signal underlying issues such as heart disease, liver problems, or certain cancers. It’s also used alongside other tests to monitor conditions like anemia or muscle disorders.
What Does a High or Low LDH Level Mean?
Elevated LDH levels may indicate damaged or stressed cells, often seen in conditions like heart attacks, liver disease, or infections. Low levels are less common but could suggest certain blood disorders or severe muscle wasting.
Common Conditions Linked to LDH Levels
High LDH is frequently associated with conditions like myocardial infarction (heart attack), liver cirrhosis, hemolytic anemia, or certain cancers. It may also appear in infections or severe muscle injuries.
Sample Collection and Preparation
This test uses a blood sample drawn from a vein, typically in your arm. The blood is processed into serum (the liquid part after clotting) for testing. No special preparation is needed, but fasting may be advised depending on your doctor’s instructions.
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 Macro Test (Serum)
Frequently asked questions
What might cause abnormal LDH levels?
How long does it take to get 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