Helps differentiate between transudative and exudative pleural effusions based on fluid analysis.
Use this Light's Criteria calculator to compare pleural fluid and serum protein and LDH values against the common exudative effusion thresholds. It is designed for fast clinical education and scenario review when the lab values are already known. The result highlights whether any Light's Criteria threshold is met, then points you to adjacent medical and lab calculators for related fluid, kidney, protein, and osmolarity questions.
Start with your values, or try a preset.
Enter pleural fluid protein and serum protein in g/dL.
Enter pleural fluid LDH and serum LDH in U/L.
Review the protein ratio, LDH ratio, and final criteria result.
Use related medical calculators when the broader clinical question involves renal function, protein concentration, or lab solution values.
See the inputs and their calculated results.
Pleural Fluid Protein (g/dL): 4.5 g/dL; Serum Protein (g/dL): 6.5 g/dL; Pleural Fluid LDH (U/L): 250 U/L; Serum LDH (U/L): 200 U/L
LDH Ratio (Pleural Fluid / Serum): 1.25; Protein Ratio (Pleural Fluid / Serum): 0.6923076923; Light's Criteria Met: Yes, the effusion is likely exudative.; Is Exudative?: Yes
Pleural Fluid Protein (g/dL): 2.5 g/dL; Serum Protein (g/dL): 7 g/dL; Pleural Fluid LDH (U/L): 100 U/L; Serum LDH (U/L): 300 U/L
LDH Ratio (Pleural Fluid / Serum): 0.3333333333; Protein Ratio (Pleural Fluid / Serum): 0.3571428571; Light's Criteria Met: No, the effusion is likely transudative.; Is Exudative?: No
Pleural Fluid Protein (g/dL): 3 g/dL; Serum Protein (g/dL): 6 g/dL; Pleural Fluid LDH (U/L): 150 U/L; Serum LDH (U/L): 250 U/L
LDH Ratio (Pleural Fluid / Serum): 0.6; Protein Ratio (Pleural Fluid / Serum): 0.5; Light's Criteria Met: Yes, the effusion is likely exudative.; Is Exudative?: Yes
A little more context for your results.
Light's Criteria helps distinguish exudative from transudative pleural effusions using pleural fluid protein, serum protein, pleural fluid LDH, and serum LDH relationships.
Yes. In the usual rule, an effusion is considered likely exudative when at least one of the protein ratio, LDH ratio, or LDH threshold criteria is met.
No. It is an educational calculator for known lab values. Clinical context, imaging, diagnosis, and treatment decisions require a qualified clinician.
Explore practical health calculators for BMI, due dates, age tracking, calorie planning, and other everyday estimates.
Continue with another tool on a related topic.
Compare a bone age already assessed by a clinician with chronological age in years and months. This tool calculates the age difference; it does not read X-rays, determine skeletal maturity or diagnose a condition.
Calculates the osmolarity of a solution based on the molar concentration of solutes.
Estimates Glomerular Filtration Rate (GFR) using the Modification of Diet in Renal Disease (MDRD) equation. GFR is a measure of kidney function.
Estimates a woman's risk of developing invasive breast cancer over the next 5 years and lifetime. This calculator uses the Gail Model, which considers factors such as age, race, personal history of breast biopsies, family history of breast cancer, and age at first menstrual period and childbirth.
This calculator is for educational use only and does not replace clinical judgment or medical advice.