LDH
Also known as: Lactate Dehydrogenase
What Does LDH Measure?
Lactate Dehydrogenase (LDH) is an enzyme found in nearly every cell of the body that plays a critical role in energy production. Specifically, it catalyzes the conversion of lactate to pyruvate (and vice versa) as part of the anaerobic respiration process. A blood test measuring LDH levels reflects the total amount of this enzyme circulating in the bloodstream, which under normal circumstances is relatively low since healthy cells keep LDH contained within their membranes.
Why Does LDH Matter?
LDH is a sensitive marker of cellular damage and tissue injury. When cells are stressed, damaged, or destroyed — due to disease, injury, or lack of oxygen — they release LDH into the bloodstream, causing levels to rise. Because LDH is present in so many tissue types (heart, liver, kidneys, muscles, red blood cells, and lungs), elevated levels serve as a general signal that something is wrong, prompting further investigation. Clinicians use LDH to monitor conditions such as hemolytic anemia, liver disease, heart attack, certain cancers, and muscle disorders, as well as to track disease progression and response to treatment.
Normal Ranges
Males
135–225 U/L
Females
135–214 U/L
Children
Varies by age; newborns: 160–450 U/L; older children gradually approach adult values
Causes of High Levels
- Hemolytic anemia or other red blood cell destruction disorders
- Liver disease including hepatitis, cirrhosis, or liver damage from toxins
- Heart attack (myocardial infarction) causing cardiac muscle cell death
- Cancer, particularly lymphoma, leukemia, and metastatic cancers
- Muscle injury or muscular dystrophy releasing muscle cell LDH
- Pulmonary embolism or lung infarction causing lung tissue damage
Causes of Low Levels
- Reactive hypoglycemia in some individuals leading to reduced metabolic enzyme activity
- Genetic LDH deficiency (rare inherited condition affecting LDH subunit production)
- High-dose vitamin C (ascorbic acid) supplementation can artificially lower measured LDH in some assays
How to Improve Your LDH
Diet
- Eat an antioxidant-rich diet with colorful fruits and vegetables (berries, leafy greens, tomatoes) to reduce oxidative stress and cellular damage
- Limit alcohol consumption, as alcohol directly damages liver cells and raises LDH
- Increase omega-3 fatty acids from fatty fish (salmon, mackerel, sardines) or walnuts to reduce systemic inflammation
- Stay well-hydrated with water throughout the day to support kidney function and cellular health
- Reduce processed foods and trans fats that promote inflammation and increase cellular stress
Supplements
- Coenzyme Q10 (100–200 mg/day) supports mitochondrial energy production and may reduce cellular stress markers
- N-acetylcysteine (NAC, 600 mg/day) acts as a precursor to glutathione and supports cellular protection
- Milk thistle (silymarin, 140 mg 2–3 times daily) supports liver cell integrity and may help lower liver-derived LDH
- Vitamin E (400 IU/day) as a fat-soluble antioxidant that protects cell membranes from damage
- Magnesium (300–400 mg/day) supports enzymatic reactions and muscle cell health
Related Biomarkers
Frequently Asked Questions
What does it mean if my LDH is high?
An elevated LDH level indicates that cells somewhere in your body are being damaged or destroyed and releasing this enzyme into your bloodstream. The cause can range from minor (intense exercise the day before the test) to serious (cancer, heart attack, liver disease, or hemolytic anemia). Because LDH is non-specific — meaning it comes from many different tissues — a high result alone cannot tell your doctor exactly where the problem is. Your doctor will typically order additional tests to identify the source and cause of the elevation.
Can exercise raise LDH levels?
Yes. Strenuous or intense physical exercise causes microscopic muscle fiber damage, which releases LDH (along with creatine kinase) into the bloodstream. This is a normal physiological response and usually resolves within 24–72 hours of rest. If you have a scheduled LDH blood test, it is advisable to avoid very intense workouts for at least 24–48 hours beforehand so that exercise-related elevations do not confuse your results.
Is LDH used to diagnose cancer?
LDH is not a cancer-specific diagnostic test, but it is a useful tumor marker in certain contexts. Elevated LDH is commonly seen in lymphoma, leukemia, testicular cancer, melanoma, and widely metastatic cancers. In these diseases, LDH levels often correlate with tumor burden and are used to help stage the disease, predict prognosis, and monitor response to treatment. However, because many non-cancerous conditions also raise LDH, it cannot be used alone to diagnose or rule out cancer.