Pulmonary

Light's Criteria Calculator

Pleural effusion classification — transudative vs exudative

Calculate Light's

Pleural Protein (g/dL)

Serum Protein (g/dL)

Pleural LDH (U/L)

Serum LDH (U/L)

Upper Normal LDH (U/L)

Clinical use

Use this calculator for pleural effusion classification — transudative vs exudative in thepulmonary workflow. It is decision support and should be interpreted with the patient context, local protocols, and clinician judgment.

Interpretation

Meeting any 1 of 3 criteria = exudative. Sensitivity 98% but specificity 83%. If borderline exudate on diuretics, consider serum-effusion albumin gradient.

Required inputs

Pleural Protein
Serum Protein
Pleural Ldh
Serum Ldh
Upper Normal Ldh

Evidence and limitations

This page cites 1 published reference. Confirm units and inclusion criteria before applying the output; calculators do not replace assessment, escalation, or local policy.

References

Light RW et al. Ann Intern Med 1972;77:507-513

Frequently asked questions

What is the Light's Criteria?

Light's Criteria is a clinical calculator used for Pleural effusion classification — transudative vs exudative.

How do I interpret the Light's Criteria?

Meeting any 1 of 3 criteria = exudative. Sensitivity 98% but specificity 83%. If borderline exudate on diuretics, consider serum-effusion albumin gradient.