Lactate Dehydrogenase (LDH) Isoenzyme Profile (Serum/Plasma)
This test measures different forms (isoenzymes) of the enzyme lactate dehydrogenase (LDH) in your blood. LDH is involved in energy production, and its isoenzymes can help identify where in your body damage or disease may be occurring.
["LDH isoenzyme testing helps pinpoint specific tissue damage beyond general enzyme levels alone."]
Key facts at a glance
- LOINC
- 51510-6
- Short code
- LDH1 CFr CSF Elph
- Synonyms
- LDH1 CFr CSF Elph
- Category
- chemistry
- Sample
- csf
- 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
- 1-2 mL
- Stability
- Immediate analysis required, Refrigerated: 1h
- Hemolysis max
- 200
- TAT
- 4–24 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms like chest pain, shortness of breath, or unexplained fatigue, especially if other tests suggest possible heart, muscle, or liver issues. It’s also used in monitoring conditions like heart attacks, muscle injuries, or certain cancers.
What to Expect Before the Test
No special preparation is usually needed. You’ll have a small needle inserted into your arm or vein to draw blood. If you’re on blood thinners, let your provider know before the test.
What the Results Mean
LDH isoenzyme results show which forms (e.g., LDH-1, LDH-2) are elevated. Higher levels of certain isoenzymes can indicate damage to specific tissues, such as the heart (LDH-1), muscle (LDH-3), or liver (LDH-5). Your provider will interpret these results in the context of your symptoms and other tests.
Common Conditions Monitored
This test helps diagnose or track conditions like myocardial infarction (heart attack), muscle injuries (e.g., from trauma or exercise), liver disease, or certain cancers (e.g., lymphoma). It’s also used in research or follow-up for suspected tissue damage.
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 Isoenzyme Test
Frequently asked questions
What questions might you have about this test?
How long will I need to wait for results?
Can I eat or drink before this test?
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