From the Guidelines
Elevated lactate dehydrogenase (LDH) levels are associated with a worse prognosis in various conditions, including cancers, and should be interpreted in the context of clinical presentation and other laboratory findings. Normal LDH blood levels typically range from 140-280 U/L for adults, though reference ranges may vary by laboratory. Elevated LDH suggests cellular damage as this enzyme is released when cells are injured or die. High LDH levels can occur in many conditions including myocardial infarction, pulmonary embolism, hemolysis, liver disease, certain cancers (particularly lymphomas and leukemias), muscle damage, and severe infections, as noted in studies such as 1.
Key Considerations for LDH Interpretation
- The pattern of LDH elevation can provide diagnostic clues - for example, LDH-1 elevation is associated with heart damage while LDH-5 increases with liver disease.
- When interpreting LDH results, it's essential to consider clinical context and other laboratory findings, as LDH alone lacks specificity.
- Serial measurements are often more valuable than single readings, particularly when monitoring disease progression or treatment response.
- Extremely high LDH levels (>1000 U/L) may indicate more severe tissue damage or aggressive malignancies and warrant prompt investigation, as seen in conditions like osteosarcoma where elevated serum LDH level is associated with a worse prognosis 1.
- LDH serves as a useful biomarker because it exists in virtually all body tissues and increases rapidly following cellular injury.
Clinical Application
In clinical practice, LDH levels are used in conjunction with other markers for diagnosing and monitoring various conditions. For instance, in testicular cancer, LDH is one of the serum tumor markers used, along with alpha-fetoprotein (AFP) and β-human chorionic gonadotropin (β-HCG), for diagnosing, determining prognosis, and assessing treatment outcome, as discussed in 1. Similarly, in the context of diffuse large B-cell lymphoma, elevated LDH is a criterion for considering prophylaxis against central nervous system relapse, highlighting its role in risk stratification and management decisions 1.
Conclusion is not allowed, so the answer ends here.
From the Research
LDH Interpretation
LDH (lactate dehydrogenase) is an enzyme that plays a crucial role in energy production and can be used as a diagnostic tool in various medical conditions.
- LDH levels are commonly increased in cancer patients and are associated with poor clinical outcome and resistance to therapy 2.
- Elevated LDH levels are also associated with advanced disease and poor survival in patients with multiple myeloma 3.
- In critically ill patients, high LDH levels are linked to higher mortality rates 4.
- LDH has different isoforms, which vary in their biochemical properties and have different substrate affinity, inhibition constants, and electrophoretic mobility 5.
- LDH isoenzyme 1 can be used in the diagnosis of myocardial infarction, with a new immunochemical method showing better discrimination between patients with and without myocardial infarction compared to total lactate dehydrogenase 6.
Clinical Significance
- LDH is an important diagnostic biomarker for various diseases, including cancer, thyroid disorders, and tuberculosis 5.
- Abnormal LDH levels can indicate tissue damage and organ dysfunction, making it a useful tool in clinical diagnosis 5.
- The measurement of LDH isoenzymes, such as LDH-1, can provide additional information in the diagnosis of specific conditions, like myocardial infarction 6.
Diagnostic Applications
- LDH measurements can be used to support the diagnosis of cancers, such as multiple myeloma, and to monitor the effects of cancer treatment 2, 3.
- Elevated LDH levels can aid in the early identification of mortality risk in critically ill patients 4.
- The determination of LDH isoenzymatic activities can provide valuable information in the diagnosis, prognosis, and prediction of cancer diseases 2.