×
MedSchool: Ace Your OSCEsThe Medical Company
 
 
 
 
 
GET - On the App Store
View
Test Findings
 
 

Positive Light's Criteria

 
Bookmark

Overview

Light's criteria are used to determine the nature of a pleural fluid sample, and narrow down the differential diagnosis of a pleural effusion. 
A pleural fluid sample is most likely exudate if one or more of the criteria are met.
  • Criteria

  • Pleural fluid : serum protein ratio >0.5
  • Pleural fluid : serum LDH ratio >0.6
  • Pleural fluid LDH > ⅔ of upper limit of normal serum LDH
  • Causes of Positive Light's Criteria

  • Malignancy
  • Infection - parapneumonic effusion, empyema, viral, fungal, TB, ruptured abscess / cyst
  • Pulmonary embolism (90% exudative)
  • Autoimmune disease - rheumatoid pleuritis, SLE
  • Pancreatitis
  • Haemothorax
  • Chylothorax
  • Asbestosis
  • Uraemia
  • Oesophageal rupture
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Want more info like this?
  • Your electronic clinical medicine handbook
  • Guides to help pass your exams
  • Tools every medical student needs
  • Quick diagrams to have the answers, fast
  • Quizzes to test your knowledge
Sign Up Now
   
 
 

Snapshot: Initialising...