LDH (lactate dehydrogenase) tests measure the amount of the LDH enzyme in the blood, which is released when cells are damaged or die; higher levels indicate increased cell turnover or tissue injury rather than a specific disease.

As a cancer indicator, elevated LDH can reflect greater tumor burden, rapid tumor cell breakdown, or aggressive disease and is used as a nonspecific prognostic and monitoring marker in cancers such as lymphoma, melanoma, testicular cancer and some leukemias—but it is not diagnostic on its own because many non‑cancer conditions (e.g., heart, liver injury, hemolysis, infections) also raise LDH.

LDH is measured from a small venous blood sample drawn by a trained phlebotomist at a clinic or laboratory; the blood is collected into a serum or plasma tube and sent to the lab for analysis. Care is taken to avoid hemolysis (ruptured red blood cells can falsely raise LDH), and the sample is processed promptly per the lab’s instructions. No special fasting is usually required, though your provider may give specific instructions (for example, avoid strenuous exercise before the draw); LDH results are interpreted together with other clinical information rather than alone.

Lactate dehydrogenase (LDH) is a common enzyme released with tissue damage; a single LDH result is non‑specific and cannot diagnose cancer. Elevated LDH can occur with many conditions — muscle injury, hemolysis, liver disease, infection, intense exercise — so a high value does not by itself mean you have cancer.

In people with known cancer, higher LDH levels often correlate with greater tumor burden or more aggressive disease in certain cancers (for example some lymphomas, leukemias, melanoma and others) and can be used as a prognostic marker or to help monitor response to treatment when trended over time. A normal LDH does not rule out cancer, and the significance of any result depends on your baseline, symptoms, imaging, and other tests.

Interpret your LDH relative to the lab’s reference range and discuss trends and possible non‑cancer causes with your clinician; repeat testing, checking for hemolysis in the sample, or additional specific tests may be needed to clarify why your LDH is high or low.

LDH measures an enzyme released by damaged or dying cells, so elevations are nonspecific — they occur with many noncancer conditions (hemolysis, liver disease, infection, tissue injury) as well as with malignancy. Because of that, a single LDH result cannot diagnose cancer, and a normal LDH does not rule it out.

Where LDH is most useful is as an adjunctive marker in context: in some cancers (for example certain lymphomas, melanoma and germ‑cell tumors) levels often correlate with tumor burden and prognosis, and serial LDH trends can help monitor response to therapy. Interpretation always requires correlation with clinical exam, imaging, biopsy and other laboratory tests; LDH should never be used alone to make or exclude a cancer diagnosis.

How often to test LDH is individualized — it’s measured at diagnosis (baseline), routinely during treatment (commonly before treatment cycles or at each oncology visit) and during follow‑up; many clinicians check it every 1–3 months early after treatment and then space checks out (for example every 3–12 months) depending on cancer type, stage, treatment response and overall clinical plan.

Follow your oncologist’s schedule — LDH can change quickly, so if you have new or worsening symptoms between visits ask for an earlier test.

No — LDH (lactate dehydrogenase) test results are not diagnostic for cancer. Elevated or low LDH can reflect tissue damage, cell turnover, inflammation, or overall physiological stress and therefore highlight patterns of imbalance or resilience—not a medical diagnosis on their own.

LDH values must be interpreted in the context of symptoms, clinical examination, medical history, imaging, and other laboratory or biomarker data by a qualified clinician; abnormal LDH may prompt further investigation but cannot confirm or exclude cancer by itself.

LDH (lactate dehydrogenase) is a non‑specific marker of tissue damage that can be elevated for many reasons — including cancer activity, liver disease, hemolysis, infection or muscle injury — so “improving” LDH requires identifying and treating the underlying cause. If cancer is the reason, effective cancer therapy often brings LDH down; your oncologist will interpret the result alongside imaging and other tests and recommend specific treatment or further workup.

Practical steps you can take while working with your care team: follow the prescribed cancer or medical treatments, treat any infections or liver problems, avoid strenuous exercise 24–48 hours before a repeat test (exercise and recent muscle injury can raise LDH), stay well hydrated, limit alcohol, and review medications/supplements with your clinician (do not stop anything without medical advice). Your doctor will advise on timing for repeat LDH measurements and the best plan to monitor and address abnormal results.