From the Guidelines
Elevated Lactate Dehydrogenase (LDH) levels are a nonspecific marker of tissue damage or cell death, and can be associated with a variety of conditions, including myocardial infarction, liver disease, various cancers, hemolysis, and muscle damage, as stated in 1. The significance of elevated LDH levels lies in their ability to indicate cellular injury or lysis, which can occur in numerous clinical contexts.
Conditions Associated with Elevated LDH
- Myocardial infarction
- Liver disease
- Various cancers
- Hemolysis
- Muscle damage As noted in 1, almost anything that results in cellular lysis or injury can lead to elevations of LDH, making it a valuable but nonspecific marker.
Clinical Utility of LDH
While LDH is not specific to any particular condition, its measurement can serve as a diagnostic tool to alert clinicians to the presence of tissue damage or cell death.
Limitations of LDH as a Diagnostic Marker
The lack of specificity of LDH elevation limits its utility in diagnosing specific conditions, as it can be elevated in a wide range of diseases and conditions, as seen in 1 and 1.
Prognostic Value of LDH
However, the only proven utility of LDH is for prognosis of chemotherapy-naïve patients with histopathologically diagnosed metastatic germ cell tumors, as stated in 1. In clinical practice, interpreting LDH results requires consideration of the patient's overall clinical context, including medical history, physical examination, and other laboratory findings.
Isoenzymes of LDH
Although patterns of elevation across five different LDH isoenzymes (LDH-1 through LDH-5) can help narrow down the source of tissue damage, this detailed analysis has become less common with the advent of newer, more specific biomarkers, as mentioned in the example answer. In summary, elevated LDH levels should prompt further investigation to determine the underlying cause of tissue damage or cell death, as stated in 1.
From the Research
Significance of Elevated Lactate Dehydrogenase (LDH)
Elevated Lactate Dehydrogenase (LDH) is a significant biomarker for various diseases, including:
- Cancer: High LDH levels are associated with cancer, particularly metastatic cancer and hematologic malignancies 2, 3
- Liver disorders: LDH is elevated in liver diseases, such as liver metastases 2
- Infections: Elevated LDH is also associated with infections, such as tuberculosis 4
- Thyroid disorders: LDH is a diagnostic biomarker for thyroid disorders 4
- Tissue damage: LDH is released into the bloodstream when tissues are damaged, making it a marker for tissue injury 5, 6
Clinical Implications
The clinical implications of elevated LDH include:
- Diagnostic value: LDH is a valuable diagnostic biomarker for various diseases, including cancer, liver disorders, and infections 4, 2
- Prognostic value: High LDH levels are associated with poor prognosis, including increased mortality and major in-hospital complications 2
- Therapeutic target: LDH is a potential therapeutic target for cancer treatment, with the goal of blocking certain metabolic pathways to stop tumor growth 3
Biochemical Properties
The biochemical properties of LDH include:
- Isoenzymes: LDH has five isoforms, each with different substrate affinity, inhibition constants, and electrophoretic mobility 4
- Cellular location: LDH is predominantly found in the cytoplasm, but also has a multi-organellar location 4
- Metabolic role: LDH plays a key role in cellular metabolism, particularly in the conversion of glucose to pyruvic acid during aerobic glycolysis 5