What is LDH? Your Complete Guide
LDH is an enzyme found in almost all body tissues — heart, liver, kidneys, muscles, and blood cells. It's released when cells are damaged, making it a general marker of tissue injury rather than specific to one organ.
💡Simply Explained
LDH is like a universal alarm bell that goes off when any cells in your body are damaged. It doesn't tell you which room the fire is in, but it definitely tells you something is wrong somewhere. Doctors then use other tests to find the exact location.
📏Normal Range
Typical reference range. Your lab may use slightly different values.
⬆️What High LDH Means
Possible Causes
- Hemolytic anemia (red blood cell destruction)
- Liver disease (hepatitis, cirrhosis)
- Heart attack or heart failure
- Cancer (lymphoma, leukemia)
- Intense exercise or muscle injury
Foods That Can Help
- Identify the source — get LDH isoenzymes if available
- Check liver function, cardiac markers, and CBC
- Rule out hemolysis (check haptoglobin, reticulocyte count)
- If very high with other symptoms, investigate for malignancy
- Retest to rule out hemolyzed sample (common false positive)
⬇️What Low LDH Means
Possible Causes
- Genetic LDH deficiency (rare, usually harmless)
- Generally not clinically significant
Foods That Can Help
- No specific action needed
- Rare genetic variants are generally harmless
🏃Lifestyle Actions
If Your LDH Is High
- Request a repeat test to rule out sample hemolysis
- Get organ-specific tests: liver enzymes (SGOT/SGPT), cardiac markers (troponin), CBC with reticulocyte count
- Rest if due to intense exercise — retest after 48 hours of rest
- Follow up on cancer screening if indicated
- Treat the underlying condition identified
If Your LDH Is Low
- No action typically required
- Mention to your doctor at next visit if consistently low
🩺When to See a Doctor
High LDH
Very high LDH (>500 U/L) with symptoms like severe fatigue, jaundice, chest pain, or unexplained weight loss needs medical evaluation within a few days. Rapidly rising LDH may indicate aggressive disease.
Low LDH
Low LDH is not a clinical concern and requires no urgent action.
🎯Did You Know?
LDH is so abundant in your body that even slight cell damage releases it. Vigorous exercise can raise your LDH by 2-3 times — so if you ran a marathon yesterday, your LDH will be sky-high today, and that's completely normal!
❓Frequently Asked Questions
What is LDH?
LDH is like a universal alarm bell that goes off when any cells in your body are damaged. It doesn't tell you which room the fire is in, but it definitely tells you something is wrong somewhere. Doctors then use other tests to find the exact location.
What is the normal range for LDH?
The typical normal range for LDH is 140–280 U/L.
What causes high LDH?
Hemolytic anemia (red blood cell destruction). Liver disease (hepatitis, cirrhosis). Heart attack or heart failure.
What causes low LDH?
Genetic LDH deficiency (rare, usually harmless). Generally not clinically significant.
How can I check my LDH levels?
You can check your LDH levels with a routine blood test. Upload your lab report to ScanHealth for an instant, plain-language explanation.
Check Your LDH Results Instantly
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Upload Your ReportThis guide is for informational purposes only and does not constitute medical advice. Reference ranges may vary by lab. Always consult a qualified healthcare provider for diagnosis and treatment.