Originalpublikation
Light RW, Macgregor MI, Luchsinger PC, Ball WC Jr. Pleural effusions: the diagnostic separation of transudates and exudates. An effusion is an exudate if the pleural/serum protein ratio exceeds 0.5, the pleural/serum LDH ratio exceeds 0.6, or pleural LDH exceeds two-thirds of the upper limit of normal for serum — sensitivity for exudates was ~99%.
Annals of Internal Medicine, 1972
Leitlinie
BTS and ATS pleural-disease guidance endorse Light’s criteria as the first-line test; because they misclassify ~25% of transudates as exudates (often in diuretic-treated heart failure), a serum–pleural fluid protein or albumin gradient is recommended when the clinical picture suggests a transudate.