Lactate Dehyderogenase (LDH)-Pleural Fluid(1ml)

High LDH in pleural fluid usually indicates an exudative effusion, reflecting inflammation, infection (including empyema), malignancy, pulmonary embolism, or tissue breakdown. It meets Light’s criteria when pleural LDH is >2/3 the upper limit of normal serum LDH or pleural/serum LDH ratio >0.6. Clinical context and additional tests (pH, glucose, microscopy/culture, cytology) guide diagnosis and management.

Elevated LDH is a non‑specific marker of tissue injury or inflammation. It can be raised in many conditions — including infections such as tuberculosis — but a high LDH alone does not mean you have TB. Diagnosis requires specific tests (microbiology, nucleic acid tests, chest imaging) and clinical assessment. Discuss abnormal LDH with your clinician to determine appropriate follow‑up.

High LDH (lactate dehydrogenase) signals cell or tissue damage but is non‑specific. Causes include hemolysis, heart attack, liver or muscle injury, infections, and some cancers. Elevated LDH prompts further evaluation—repeat testing, targeted blood tests, imaging, or specialist referral—to identify and treat the underlying condition. The significance and prognosis depend on the cause and degree of rise.

The LDH test measures blood levels of lactate dehydrogenase, an enzyme released when cells are damaged. Elevated LDH can indicate lung injury or inflammation—seen in pneumonia, interstitial lung disease, pulmonary embolism, or severe viral infections—and helps assess disease severity and treatment response. It is not lung-specific, so results are interpreted with symptoms, imaging and other tests to find the cause.

Elevated LDH is seen in many cancers, especially hematologic malignancies (aggressive non‑Hodgkin lymphoma, leukemias, multiple myeloma), germ‑cell/testicular tumors, melanoma, small‑cell lung cancer and hepatocellular carcinoma. It is also common with metastatic solid tumors (breast, lung, gastrointestinal, pancreatic) where high tumor burden or necrosis exists. LDH is nonspecific but often reflects aggressive disease and has prognostic value.

The pleural space normally contains only a thin film of fluid—typically about 5–20 milliliters (around a tablespoon or less). This small volume lubricates the visceral and parietal pleura, allowing smooth lung movement during breathing and maintaining surface tension. Common causes of increased fluid include infection, heart failure, or malignancy, and symptoms may include breathlessness or chest pain.