From the Guidelines
LDH testing is not recommended for patients with asymptomatic stage 0-II cutaneous melanoma, but it is useful as a prognostic marker in patients with stage IV disease. The decision to order LDH testing should be based on the patient's symptoms and stage of disease. According to the guidelines of care for the management of primary cutaneous melanoma 1, laboratory or imaging studies, including LDH testing, are only recommended to evaluate signs or symptoms of metastasis.
For patients with stage IV disease, elevated LDH levels are associated with worse survival and may predict response to therapy 1. The American Joint Committee on Cancer (AJCC) staging system incorporates serum LDH level for the classification of stage IV disease. I recommend ordering LDH testing for patients with stage IV cutaneous melanoma, as it provides valuable prognostic information. However, for patients with lower stages of disease (stage I-III), LDH testing is not recommended due to its lack of sensitivity and specificity for detecting metastasis 1.
In general, LDH testing can be useful in evaluating tissue damage and cell death in various conditions, including myocardial infarction, pulmonary embolism, and certain cancers. However, in the context of cutaneous melanoma, its use should be limited to patients with stage IV disease or those with symptoms suggestive of metastasis. The normal range for LDH is typically 140-280 U/L, but reference ranges may vary by laboratory, and results should be interpreted alongside other clinical findings and more specific tests to determine the source of tissue damage.
Some studies have also evaluated the role of LDH in pleural disease, where it can help differentiate between exudative and transudative pleural effusions 1. However, this is not directly relevant to the management of cutaneous melanoma. In summary, LDH testing should be ordered judiciously, taking into account the patient's symptoms, stage of disease, and the potential benefits and limitations of the test.
From the Research
Reasons to Order LDH
- LDH is used as a marker of cardiac injury and an enzyme in anaerobic glycolysis, and high serum lactate dehydrogenase is suggested as a predictor of cardiac insufficiency at follow-up in elderly patients with acute myocardial infarction 2.
- The efficiency of lactate dehydrogenase isoenzyme determination for the diagnosis of acute myocardial infarction has been studied, and the results show that LDH-1 value above 90 U/L is the most efficient factor for diagnosing AMI 3.
- LDH isoenzyme 1 has been found to be better than total lactate dehydrogenase in discriminating between patients with and without myocardial infarction, and its efficiency is comparable to that of CK-MB on day 1 4.
- Recent studies have shown that lactate dehydrogenase seems to be a promising biomarker of adverse left ventricular remodeling, and higher levels of LDH are associated with lower odds for favorable reverse remodeling in patients with MI 5.
- The lactate dehydrogenase to serum albumin ratio (LAR) has been found to be associated with in-hospital mortality in patients with pulmonary embolism, and monitoring LAR may be promising as a prognostic marker among patients with acute PE 6.
Clinical Applications of LDH
- LDH can be used to diagnose myocardial infarction, especially in patients with slight to moderate elevation of total serum LDH values 3.
- LDH can be used to predict cardiac insufficiency at follow-up in elderly patients with acute myocardial infarction 2.
- LDH can be used as a biomarker of adverse left ventricular remodeling in patients with MI 5.
- LDH can be used as a prognostic marker in patients with pulmonary embolism 6.