What is LDH? How Our Bodies Generate Energy and Heal Tissue


LDH stands for lactate dehydrogenase, which is a crucial enzyme that aids in the process of cellular respiration. Cellular respiration is the process in which our bodies convert the glucose from the food we eat, into energy for our cells.

LDH can be found in essentially all of the body’s tissues, with the red blood cells, liver, kidney, and muscles containing the largest concentration of it. LDH is released into the bloodstream or other bodily fluids when these tissues sustain injury or damage.

It is always typical to have some LDH in our bloodstream, as it is a byproduct of our bodies replacing older, nonfunctioning cells with newer, healthier ones. However, more severely elevated levels of LDH can be indicative of disease or health complications.


LDH Blood Test: What is it Used For?


An LDH blood test can be used to diagnose and track a variety of medical disorders. Lactate dehydrogenase measurements can reveal information about tissue and cell damage brought on by more serious underlying illnesses.

While a lactate dehydrogenase test can detect elevated levels of LDH, it cannot pinpoint which tissues are being affected. As a result, medical professionals frequently request additional LDH Isozymes tests to work in tandem with LDH testing to aid in the diagnosis of diseases. An assessment of LDH levels is often requested at the behest of a doctor who believes their patient is suffering from an acute or long-term illness that is causing tissue damage, particularly of the heart, lungs, blood, kidney, and liver. One might also receive an LDH test of bodily fluids to identify fluid buildup, and what might have caused it. 

Acute ailments develop rapidly and may present severe symptoms. These symptoms could be indicative of infection, organ failure, or a drug reaction. Chronic afflictions usually advance slowly over time and require recurrent testing to track the progression of illnesses such as anemia, hepatitis, and liver disease. There are a host of situations that could call for the use of an LDH test since it is a nonspecific marker of cell damage, but many consider its work in conjunction with cancer treatment to be the most significant. Lactate dehydrogenase testing may be used on patients with specific cancers such as melanoma, lymphoma, and testicular cancer to assess the severity of the illness and/or the patient’s prognosis. LDH testing can also be used to track the effectiveness of chemotherapy treatments in the patient’s body.


After the LDH Test: How Do I Interpret My Results?


Taking an LDH test involves a simple blood sample being drawn in a medically safe environment. This blood test typically does not require any particular preparation. After the test, the patient should have access to the results within a few business days. The test report should include LDH levels as well as reference ranges for what can usually be considered healthy ranges of LDH. It is essential that a healthcare provider review results with their patient, as reference ranges can differ between laboratories. Due to the non-specific nature of lactate dehydrogenase testing, the patient’s medical history, symptoms, and results from tests taken in conjunction with an LDH panel, must be taken into account when interpreting elevated levels of LDH. Health conditions characterized by elevated LDH can include shock, hepatitis, drug reactions, infection, anemia, muscular dystrophy, and cancer. While increased LDH concentration in the blood does not cause concern by itself, further examination is required if the increase presents itself in tandem with symptoms of other diseases. Monitoring LDH has proven helpful in evaluating the progression and severity of cancer. Drastically elevated levels of LDH may signify a “high tumor burden,” a term used to signify the presence of a greater number of cancer cells in the body. If measured routinely, LDH can also serve as a cancer marker. A drop in LDH could be a sign that the cancer is responding positively to treatment.


Is My LDH Blood Test Result Accurate?


Despite its many advantages and versatility, LDH testing does not come without limitations. Since LDH is so widespread throughout the body other test results are necessary to act as indicators of the root of the problem. Without other symptoms, the cause of heightened lactate dehydrogenase can remain uncertain. In some cases, abnormal test results can arise from scenarios in which illness plays no factor. High test results can occur from heavy exercise, prescription medications, recreational drugs, or even mishandling of the patient’s blood sample. Low test results can arise from the presence of certain vitamins in the body. Overall, it is critical to take into account the patient’s entire medical condition as a whole, using an LDH test as merely one piece of the puzzle. Medical history and presenting symptoms must be used as context to interpret the results of an LDH test. Retesting and performing additional tests could be necessary to ensure a reliable, accurate diagnosis. Doing so helps determine if increased LDH is merely superficial tissue damage or something much more serious lurking beneath the surface.




Claps, G., Faouzi, S., Quidville, V., Chehade, F., Shen, S., Vagner, S., & Robert, C. (2022). The multiple roles of LDH in cancer. Nature Reviews Clinical Oncology, 1-14.


Drent, M., Cobben, N. A., Henderson, R. F., Wouters, E. F., & van Dieijen-Visser, M. (1996). Usefulness of lactate dehydrogenase and its isoenzymes as indicators of lung damage or inflammation. European Respiratory Journal, 9(8), 1736-1742.


Forkasiewicz, A., Dorociak, M., Stach, K., Szelachowski, P., Tabola, R., & Augoff, K. (2020). The usefulness of lactate dehydrogenase measurements in current oncological practice. Cellular & Molecular Biology Letters, 25(1), 1-14.


Henry, B. M., Aggarwal, G., Wong, J., Benoit, S., Vikse, J., Plebani, M., & Lippi, G. (2020). Lactate dehydrogenase levels predict coronavirus disease 2019 (COVID-19) severity and mortality: A pooled analysis. The American journal of emergency medicine, 38(9), 1722-1726.


Inamura, N., Miyashita, N., Hasegawa, S., Kato, A., Fukuda, Y., Saitoh, A., ... & Ouchi, K. (2014). Management of refractory Mycoplasma pneumoniae pneumonia: utility of measuring serum lactate dehydrogenase level. Journal of Infection and Chemotherapy, 20(4), 270-273.


Jurisic, V., Radenkovic, S., & Konjevic, G. (2015). The actual role of LDH as tumor marker, biochemical and clinical aspects. Advances in Cancer Biomarkers, 115-124.