Wednesday, March 21, 2012

Exudate & Transudate

Hello everyone!

Whenever you find fluid in the body which is out of the circulatory system you need to differentiate whether this fluid is an exudate or a transudate (Only if it is in pathologically significant amounts!)

I'll let you know why this is important in a while.. Keep reading.

Exudate vs Transudate
More proteins.
More cells.
Mnemonic: Exudate exudes proteins.

Does not contain large plasma proteins like fibrinogen.
Has a few, if any, cells.
Mnemonic: Transudate is transparent (No proteins)

Mnemonic by Anonymous:
Relate exudate to pus & transudate to pressure differences (trans) and you'll not forget it.

All 'failures' (heart/liver/renal) are transudative causes.

I remember 'EXudate' as EXit of protein :P 
E for Evil: Infection, Malignancy
E sounds like iiii infection

Clinical significance:
This is important for the diagnosis of the underlying cause.

Exudate occurs when inflammation leads to increased capillary permeability.

Transudate occurs when there are imbalances in hydrostatic and oncotic forces in circulation. There is an intact capillary endothelial barrier which causes ultra-filtration of plasma.

If your pleural fluid is an transudate then your therapy will be diverted to the underlying congestive heart failure, cirrhosis or nephrosis.

But if your fluid is an exudate, then you have to look for infections, malignancies, empyema, rheumatoid pleuritis, embolism, etc.

We use Light's criteria for deciding whether pleural fluid is transudate or exudate.

An exudate will fulfill these criterias:
Pleural fluid protein / plasma protein > 0.5
Pleural fluid LDH / plasma LDH > 0.6
Pleural fluid LDH > 2/3 x Serum LDH Upper Limit of Normal.

Mnemonic for Light's criteria here.

We use Serum Albumin Ascites Gradient for finding out the cause of ascites.
SAAG = Albumin in serum - Albumin in ascitic fluid
If SAAG > 1.1 it's portal hypertension.
If SAAG < 1.1 it could be cancer, nephrotic syndrome, cancer, tuberculosis, etc.

Mnemonic for SAAG here.

That's all!
Hope you got it... Feel free to ask if you have any queries. I haven't covered all of it.. It's a huuuge topic.
Have a nice day ^_^

During this Mental Health Awareness month, we are educating people about therapy. You can read more about it here.


  1. transudate is transparent! (low protein levels)

    exudate exudes proteins!

    1. That's an awesome mnemonic! Thank you so much for sharing ^___^

  2. One has protein and fibrin present in it and the other doesn't.

    Relate exudate to pus & transudate to pressure differences (trans) and you'll not forget it.

    E for evil: infection malignancy
    E sounds like iiii infection

    I remember 'EXudate' as EXit of protein :P
    And all 'failures' (heart/liver/renal) are transudative causes.

  3. Adult content - warning
    Exudate- date with our ex girlfriend
    She is inflammable - associated with inflammation
    Ur permeability increased- capillary permeability increased
    U released clowdy secretions- rich in proteins
    After that u felt like flying- gravity decreased
    And ur cholesterol also decreased

  4. Very nicely 👌👌👌 explained sir


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