Light’s criteria
Distinguishes pleural transudate from exudate using fluid and serum protein and lactate dehydrogenase (LDH).
Calculate with transparency
Check the population, units and version. The result shows the formula or classification; it does not make an automatic treatment decision.
Preparing the form…
- Check the method
- Enter the data
- Check the result
Method · Limits of application
Light 1972; BTS 2023 variant: pleural/serum protein >0.5; pleural/serum LDH >0.6; pleural LDH >2/3 of serum ULN.
This implementation combines Light’s criteria with the variant documented by BTS 2023: pleural LDH above two thirds of the laboratory’s serum upper limit, which differs from the absolute cutoff in the 1972 article. Use paired pleural and serum samples and the laboratory’s own upper limit; the cutoffs are strictly greater than the thresholds. The biochemical classification does not identify the cause of the effusion. The optional albumin gradient is a complementary assessment and must not, on its own, replace clinical investigation.
Conditions of use
Check the population, units, inclusion and exclusion criteria, and version in the original source. A result alone does not establish a diagnosis, discharge decision or prescription.
Documented parameters
- Pleural fluid protein · g/dL
- Serum protein · g/dL
- Pleural fluid LDH · U/L
- Serum LDH · U/L
- Laboratory upper limit of normal for serum LDH · U/L
- Pleural fluid albumin · g/dL
- Serum albumin · g/dL
4/4 reference cases checked. Numerical tests are not clinical validation.
Relationship with cancer research
General context — relationship to be defined
A resource for general clinical contexts. This edition does not assign a specific oncological relationship; selecting it for a study requires a justified question, population and purpose.