From the Guidelines
Elevated Lactate Dehydrogenase (LDH) levels should be approached with a systematic evaluation to identify the underlying cause, as LDH is a nonspecific marker released during tissue damage. The diagnostic approach involves confirming the elevation with repeat testing if necessary, then obtaining a thorough medical history focusing on symptoms that might suggest specific organ involvement 1. A physical examination should target potential sources of tissue damage. Laboratory investigations should include complete blood count, comprehensive metabolic panel, and specific tests based on clinical suspicion such as cardiac enzymes for heart damage, liver function tests for hepatic disease, or hemolysis workup.
Key Considerations
- Imaging studies like chest X-ray or CT scans may be indicated if pulmonary, cardiac, or malignant conditions are suspected.
- In cases of significant elevation without obvious cause, further specialized testing such as bone marrow examination or tissue biopsy may be necessary.
- LDH exists in five isoenzymes distributed differently across tissues, and identifying the specific isoenzyme pattern can help localize the source of damage.
- LDH elevations occur in numerous conditions including myocardial infarction, pulmonary embolism, hemolysis, liver disease, muscle disorders, and various malignancies, so the diagnostic approach must be tailored to the clinical context rather than treating the elevated LDH itself 1.
Diagnostic Approach
- Confirm the elevation with repeat testing if necessary
- Obtain a thorough medical history focusing on symptoms that might suggest specific organ involvement
- Perform a physical examination to target potential sources of tissue damage
- Conduct laboratory investigations including complete blood count, comprehensive metabolic panel, and specific tests based on clinical suspicion
- Consider imaging studies or further specialized testing as needed This approach is supported by the most recent evidence, which emphasizes the importance of a systematic evaluation to identify the underlying cause of elevated LDH levels 1.
From the Research
Diagnostic Approach for Elevated LDH Levels
Elevated Lactate Dehydrogenase (LDH) levels can be an indicator of various underlying conditions, including malignant lymphoma, cancer, liver metastases, hematologic malignancies, and infection. The diagnostic approach for elevated LDH levels involves a thorough work-up to determine the underlying cause.
Possible Causes of Elevated LDH Levels
- Malignant lymphoma: Elevated LDH levels can be an early marker of occult malignant lymphoma, as seen in a study published in 1984 2.
- Cancer: High LDH levels are associated with the presence of cancer, particularly liver metastases and hematologic malignancies, as reported in a study published in 2014 3.
- Infection: Elevated LDH levels can also be caused by infection, as noted in a study published in 2014 3.
- Hematologic malignancies: Increased LDH levels are associated with poor survival in patients with multiple myeloma, as reported in a study published in 2011 4.
Prognostic Value of Elevated LDH Levels
- Elevated LDH levels are associated with a poor prognosis, including increased mortality rates and major in-hospital complications, as reported in studies published in 2002 5 and 2014 3.
- High LDH levels can identify subgroups of patients with very-high-risk multiple myeloma, as noted in a study published in 2011 4.
- Elevated LDH levels are inversely related to response to checkpoint inhibitors, as reported in a study published in 2020 6.
Diagnostic Tests and Procedures
- Abdominal CT scan: May be recommended as part of the diagnostic work-up for elevated LDH levels, as noted in a study published in 1984 2.
- Explorative laparotomy: May be necessary in some cases to determine the underlying cause of elevated LDH levels, as reported in a study published in 1984 2.
- Serum LDH measurements: Can be used to monitor the progression of disease and response to treatment, as noted in studies published in 2002 5 and 2014 3.