LDH tests measure the level of lactate dehydrogenase (LDH), an enzyme released into the blood when cells are damaged or broken down; higher-than-normal LDH indicates tissue injury, cell turnover, or metabolic stress rather than a specific disease.

In cancer care, elevated LDH can serve as a non‑specific indicator of high tumor burden, rapid cell turnover, or tumor‑related tissue damage and is often used as a prognostic or monitoring marker (for example in lymphoma, melanoma, and some germ‑cell tumors), but it is not diagnostic of cancer by itself and must be interpreted alongside clinical findings and other tests.

A small blood sample is taken, usually by venipuncture (a needle into a vein in your arm) and sent to the laboratory—labs typically measure LDH in serum or plasma prepared from that venous blood. In some point‑of‑care settings a fingerstick sample may be used, but venous collection is the standard for most LDH assays.

The sample must be handled properly to avoid hemolysis (rupture of red blood cells), which can artificially raise LDH results; it is labeled, processed (serum or plasma separated) and transported to the lab according to routine procedures. No special preparation such as fasting is usually required, but follow any instructions your testing location gives you about timing or medication.

Lactate dehydrogenase (LDH) is a common blood enzyme that rises when cells are damaged or destroyed; it is a non‑specific marker, so a high LDH can reflect many causes (infection, liver disease, hemolysis, muscle injury, and more) not just cancer. In some cancers (for example certain lymphomas, leukemias, melanoma and germ‑cell tumors) markedly elevated or rising LDH can correlate with greater tumor burden or more aggressive disease, while normal LDH does not rule out cancer.

LDH results are most useful as one piece of the puzzle—not a diagnostic test on their own. Trends over time and correlation with symptoms, imaging and other lab tests matter more than a single value. If your LDH is abnormal, your clinician may repeat the test, check for other causes of elevation, or order imaging/biopsy as indicated; if it’s normal, doctors will still consider the whole clinical picture. These tests are for people to understand their personal LDH levels and nothing else.

LDH (lactate dehydrogenase) is a sensitive but nonspecific enzyme marker—levels rise whenever there is tissue damage, hemolysis, liver disease, infection, or vigorous exercise—so an elevated LDH alone is not reliable for diagnosing cancer. Because it can be abnormal for many benign and non‑cancerous reasons, LDH cannot be used as a screening or definitive diagnostic test for malignancy.

In oncology LDH is most useful as an adjunct: certain cancers (for example some lymphomas, melanoma, and germ‑cell tumors) use LDH as a prognostic marker or to monitor treatment response, and trends over time are more informative than a single value. Its sensitivity and specificity vary by cancer type and clinical context, so results must be interpreted alongside clinical assessment, imaging, and tissue diagnosis; abnormal LDH typically prompts further investigation rather than providing a conclusive answer.

Frequency of LDH testing varies with cancer type, treatment phase and your doctor’s plan. Common practice is to get a baseline LDH at diagnosis, then repeat it regularly during active treatment (often before each treatment cycle or every 2–4 weeks) to monitor response, and again at the end of therapy. During follow‑up/surveillance many clinicians check LDH every 1–3 months in the first year or two, then space checks out to every 3–6 months for several years and possibly annually thereafter — but schedules differ by disease and risk of relapse.

LDH is a nonspecific marker and must be interpreted with imaging, symptoms and other lab results, so testing should follow the interval your oncology team recommends; get tested sooner if new symptoms or concerns arise.

No — LDH test results highlight patterns of imbalance or resilience — not medical diagnoses. An abnormal LDH level can signal that something is happening (for example tissue stress or changed metabolic activity), but by itself it does not confirm cancer or any specific disease.

LDH results must be interpreted alongside symptoms, clinical history, imaging and other laboratory or biomarker data by a qualified clinician who can integrate the pattern of findings and recommend appropriate follow‑up or diagnostic testing.

LDH is a non‑specific marker of tissue damage and, in oncology, often reflects tumor burden or aggressive disease rather than being a direct target itself; the most reliable way to lower LDH when it is elevated because of cancer is to treat the underlying malignancy per your oncologist’s plan (chemotherapy, targeted therapy, immunotherapy, surgery or radiation). If LDH is raised for non‑cancer reasons (liver disease, hemolysis, infection, muscle injury), addressing that specific cause—for example treating infections, managing liver conditions, correcting hemolysis or avoiding strenuous exercise—can reduce levels.

Practical steps include promptly discussing results with your treating physician or oncologist, following prescribed cancer or other therapies, avoiding heavy exercise and alcohol before repeat testing, ensuring any new or interacting medications/supplements are reviewed by your clinician, and arranging timely follow‑up tests so changes can be interpreted in context. LDH is non‑specific, so don’t attempt to “treat the number” on your own—work with your care team to target the underlying cause and monitor response. If you have new or worsening symptoms, seek medical attention promptly.