Light’s Criteria

Distinguish exudative from transudative effusions.

Medical Disclaimer

This tool is for educational and screening purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Pleural Fluid Entry

Pleural Protein

Serum Protein

Pleural LDH

Serum LDH

Upper Limit of Normal Serum LDH

Fluid Classification

EXUDATE

Exudates typically result from inflammation or malignancy, while transudates result from hydrostatic/oncotic imbalance (e.g. Heart Failure, Cirrhosis).

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About Light’s Criteria

Light's Criteria is a fundamental diagnostic tool in clinical medicine, specifically designed for the analysis of pleural fluid. It serves to accurately distinguish between exudative and transudative effusions, a critical step in determining the etiology of pleural fluid accumulation. Healthcare professionals, including physicians and medical students, utilize this criteria to guide their diagnostic process. By comparing the levels of protein and lactate dehydrogenase (LDH) in both pleural fluid and serum, Light's Criteria provides an objective framework. This distinction is invaluable for identifying underlying conditions, ranging from heart failure (transudative) to infections or malignancies (exudative), thereby informing appropriate patient management and treatment strategies.