LDH (Lactate Dehydrogenase)
An LDH (lactate dehydrogenase) test measures the amount of LDH in your blood to detect tissue damage or cellular injury throughout the body.
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What this test measures
Lactate dehydrogenase (LDH) is an enzyme present in nearly every tissue in the body, with the highest concentrations found in muscle, liver, kidneys, and red blood cells. Its primary function is converting glucose into energy during cellular respiration, making it essential for routine cell metabolism.
A certain amount of LDH circulates in the blood at all times as part of the normal lifecycle of cells: as older cells break down and are replaced, they release their LDH into the bloodstream. When tissue damage occurs from injury, disease, or infection, the rate of cell breakdown accelerates and LDH levels rise above baseline. This makes the LDH test a useful general indicator of tissue injury somewhere in the body. Because the enzyme is so widely distributed, an elevated result does not point to a specific organ on its own, but it signals that further investigation may be warranted to identify the location and cause of the damage.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing unexplained fatigue, muscle weakness, or general symptoms that may indicate tissue damage should consider LDH testing as part of their diagnostic workup.
- Those with suspected heart problems, including chest pain or other cardiovascular symptoms, may benefit from LDH testing as it can help detect heart muscle damage.
- Patients being monitored for certain cancers, as elevated LDH levels can indicate tumor growth or progression and are often used as a tumor marker in various malignancies.
- Individuals with liver disease symptoms such as jaundice, abdominal pain, or abnormal liver function tests may need LDH testing to assess liver tissue damage.
- People with suspected muscle disorders, injuries, or conditions like muscular dystrophy should consider this test to evaluate muscle tissue health and damage.
- Those being evaluated for hemolytic anemia or other blood disorders, as LDH levels often rise when red blood cells are destroyed.
- Patients with respiratory symptoms or lung disease, as LDH can be elevated in conditions affecting lung tissue such as pneumonia or pulmonary embolism.
What to expect
Preparation
No special preparation is needed for the LDH test. Patients can eat normally and take their regular medications unless specifically instructed otherwise by their healthcare provider.
Sample Type
The test requires a simple blood draw, typically taken from a vein in the arm using a small needle. The blood sample is collected in a standard tube.
Collection
At the lab location, a healthcare professional will clean the injection site, insert a small needle into a vein, and collect the blood sample. The entire process typically takes just a few minutes.
Turnaround
Results are typically available within 1-3 business days after sample collection, allowing for prompt evaluation of tissue health and cellular function.
Understanding your results
Elevated LDH suggests that tissue somewhere in the body has sustained damage, whether from a chronic condition, an acute injury, or an active disease process. Because LDH is found in so many different tissues, an abnormal result is a broad signal rather than a specific diagnosis. Healthcare providers use the LDH level as a starting point and typically order additional, more targeted tests to determine which organ or tissue is involved and what is driving the elevation.
| Population | Reference Range | Notes |
|---|---|---|
| Adult Males | 135 – 225 units per liter (U/L) | Normal range for healthy adult males |
| Adult Females | 135 – 214 U/L | Normal range for healthy adult females |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
Abnormally low levels of LDH are very rare and usually not considered harmful. Low LDH levels are very rare and usually not harmful, but they may indicate LDH deficiency. In some cases, low levels may be associated with taking large amounts of vitamin C or vitamin E supplements, or rarely, a genetic condition called lactate dehydrogenase deficiency.
What does a “High” result mean?
Having higher-than-normal LDH levels usually means you have some type of tissue damage from an injury, disease or infection --- whether chronic or acute. Elevated LDH may be associated with various conditions including kidney disease, lung disease, liver disease, muscle injury, heart attack, pancreatitis, certain infections including meningitis and HIV, and certain types of cancer including lymphoma and leukemia. LDH tests can't determine which tissues in your body are damaged. Because of this, healthcare providers often order other tests alongside LDH tests to help diagnose conditions.
Privacy & confidentiality
LDH test results are completely confidential and protected under HIPAA regulations. Results are not shared with your personal physician unless you specifically request it, are not added to your primary medical records, and do not appear on insurance explanation of benefits statements.
Frequently asked questions
Related tests
Heart Health Panel
Comprehensive cardiovascular assessment including cardiac-specific markers to differentiate heart-related LDH elevation
View TestLiver Panel
Evaluates liver-specific enzymes and function to assess hepatic causes of elevated LDH levels
View TestComplete Blood Count (CBC)
Detects hemolytic anemia and other blood disorders that can cause elevated LDH through red blood cell destruction
View TestComprehensive Metabolic Panel
Provides comprehensive organ function assessment to help identify the source of tissue damage indicated by elevated LDH
View TestRelated conditions
Last reviewed: April 2026
CPT Code: 83615
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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