Respiratory General Medicine Strong — Ann Intern Med 1972
Light's Criteria for Pleural Effusion
Distinguishes exudative from transudative pleural effusions using protein and LDH ratios.
Score interpretation
Transudate 0
0 of 3 criteria met: Transudate. None of Light's criteria met.
→ Causes: Heart failure, cirrhosis, hypoalbuminaemia, hypothyroidism. Treat underlying cause.
Exudate 1–3
1 or more criteria met: Exudate. Sensitivity 98%, specificity 83%.
→ Exudate causes: pneumonia (parapneumonic), malignancy, PE, TB, RA, pancreatitis. Further investigation: pH, glucose, cytology, cultures, ADA.
Interpretation bands for the Light's Criteria. Apply clinical judgement and local guidance.
References
- Light RW et al. Pleural effusions: the diagnostic separation of transudates and exudates. Ann Intern Med. 1972.
Related
Curated clinical cross-links plus same-class fallbacks.
Calculators
Drugs
- Methotrexate (Dermatology — Psoriasis) · Disease-Modifying Antirheumatic / Immunosuppressant
- Retinol palmitate with white soft paraffin, light liquid paraffin, liquid paraffin and wool fat · Ocular lubricant ointment
- Acetazolamide (Ménière's Disease) · Carbonic Anhydrase Inhibitor (Diuretic)
- Zinc acetate · Zinc salt (Wilson's disease)
- Dairy products · Nutritional source (calcium, protein, vitamin D)
- Sulfasalazine · Aminosalicylate / Disease-Modifying Antirheumatic Drug (DMARD)
Pathways
- Acute Asthma in Adults · BTS/SIGN British Guideline on Asthma 2019; NICE NG80
- Pulmonary Embolism Assessment · NICE NG158; ESC 2019 PE Guidelines
- Acute Exacerbation of COPD (AECOPD) · NICE NG115; GOLD 2024
- Spontaneous Pneumothorax (Adult) · BTS Pleural Disease 2023
- Atypical Pneumonia (Legionella / Mycoplasma / Chlamydophila) · BTS 2023; IDSA
- COPD Exacerbation Management · NICE NG115 / GOLD 2024
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.