Lactate Dehydrogenase (LDH) Isoenzyme Profile by Electrophoresis (Serum/Plasma)
This test measures different forms (isoenzymes) of the enzyme lactate dehydrogenase (LDH) in your blood using electrophoresis, a technique that separates proteins based on size and charge.
["LDH isoenzymes help identify where in your body abnormal enzyme activity may be occurring."]
Key facts at a glance
- LOINC
- 2539-5
- Short code
- LDH2 CFr SerPl Elph
- Synonyms
- LDH2 CFr SerPl Elph
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- 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
- 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 This Test Is Done
Doctors may order this test to investigate conditions affecting muscle, heart, liver, or red blood cells. Elevated levels of certain isoenzymes can signal damage in specific organs, such as the heart (cardiac LDH-1) or liver (LDH-5).
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.
How the Test Is Performed
A healthcare provider will draw blood from a vein in your arm using a needle. You may feel a small pinch, but it usually doesn’t cause discomfort afterward. The blood sample is then sent to a lab for electrophoresis to separate LDH isoenzymes.
What the Results Mean
Results show the relative amounts of different LDH isoenzymes, which can help pinpoint the source of tissue damage. For example, a higher proportion of LDH-1 might suggest heart muscle injury, while LDH-5 could indicate liver problems.
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.
LDH isoenzyme patterns are used to diagnose or monitor conditions like myocardial infarction (heart attack), muscle injuries, hemolytic anemia (red blood cell breakdown), or liver disease. Abnormal isoenzyme ratios can guide treatment decisions and help track disease progression.
Short name
LDH Isoenzyme Electrophoresis
Frequently asked questions
What does an LDH isoenzyme test measure?
How long does it take to get results from this test?
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