: Lactate Dehydrogenase 3 (LDH-3) Isoenzyme, Serum or Plasma, by Electrophoresis
: This test separates the different forms (isoenzymes) of lactate dehydrogenase in serum or plasma and measures the relative amount of the LDH-3 fraction, which comes mainly from the lungs and lymph tissue.
[": The LDH-3 isoenzyme test helps show which tissue may be releasing LDH into the blood."]
Key facts at a glance
- LOINC
- 2542-9
- Short code
- LDH3 CFr SerPl Elph
- Synonyms
- LDH3 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
: What Lactate Dehydrogenase (LDH) Is
: Lactate dehydrogenase is an enzyme found inside many cells of the body. When cells are damaged or turn over faster than normal, LDH leaks into the blood. Because it is present in so many tissues, a total LDH level alone cannot say where the problem is.
: What LDH-3 Isoenzyme Means
: LDH exists in several slightly different forms called isoenzymes. Electrophoresis separates them into bands, and the LDH-3 fraction is richest in lung and lymphatic tissue. Measuring this fraction can suggest that a source of LDH release lies in those areas rather than in the heart, liver, or red blood cells.
: How the Test Is Done
: A blood sample is drawn from a vein, usually in your arm, and sent to the laboratory. There, serum or plasma is separated and the LDH isoenzymes are spread out by electrophoresis so each fraction can be measured.
: What to Expect and How to Prepare
: The blood draw takes only a few minutes and feels like a brief pinch. Unless your care team tells you otherwise, no special fasting or preparation is needed. Tell your provider about any medicines you take, since some can affect results.
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.
◆Associated findings1
Short name
: LDH-3 Isoenzyme
Frequently asked questions
: Is the LDH-3 isoenzyme test a diagnosis by itself?
: Are there risks from having this blood test?
: Can my medicines change the result?
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