Sunday 29 June 2008

Pleural effusion : transudate vs exudate

Learnt about differentiating transudate and exudate based on Light's criteria.

Light's criteria :
1. Protein - pleural fluid : serum >0.5
2. LDH - plueral fluid: serum >0.6
3. LDH is more than 2/3 normal upper limit for serum

Twenty-five percent of patients with transudative pleural effusions are mistakenly identified as having exudative pleural effusions by Light's criteria. Therefore, additional testing is needed if a patient identified as having an exudative pleural effusion appears clinically to have a condition that produces a transudative effusion. In such cases albumin levels in blood and pleural fluid are measured. If the difference between the albumin levels in the blood and the pleural fluid is greater than 1.2 g/dL (12 g/L), it can be assumed that the patient has a transudative pleural effusion.

If the fluid is definitively identified as exudative, additional testing is necessary to determine the local factors causing the exudate.

According to a meta-analysis, exudative pleural effusions must meet at least one of the following criterias.
1. Pleural fluid protein >2.9g/dl
2. Pleural fuild cholesterol . 1.16mmol/l
3. Pleural ADH more than 60% of upper limit for serum

(Source : Wikipedia- pleural effusion)

2 comments:

Anonymous said...

eh.. which article u read before blogging this lah? i think i read the same thing but kenot remember...

Owners of Snowy said...

I read that questions on Medicine for medical students...And the author asked abt Light's criteria..I didn't know, so i read and decided to share it with others who don't know.