Light's criteria for pleural effusion

Separates exudative from transudative pleural effusions.

Previewv0.1.0 · Pending clinical review

Inputs

1 of 5

Pleural protein

g/dL

Serum protein

g/dL

Pleural LDH

U/L

Serum LDH

U/L

Serum LDH upper limit of normal

U/L

When to use

Pearls and pitfalls

About 25% of transudates (often diuresed heart failure) are misclassified as exudates; check the serum-to-pleural albumin gradient (above 1.2 g/dL suggests transudate).

Why use

The standard first step in effusion workup.

Exudate if any: pleural/serum protein > 0.5, pleural/serum LDH > 0.6, or pleural LDH > 2/3 of the serum upper limit of normal