- Low protein and low celularity
- Clear
- Specific gravity <1.018
- Total protein < 25g/L
- Nucleated cells <0.5 x 10e9/L
- Mesothelial cells, macrophages, low numbers of non-degenerate neutrophils
- Typically very high volume of fluid
- Due to:
- Decreased colloid osmotic pressure
- Renin - angiotensin system activation
- Hypoalbuminaemia secondary to glomerular or hepatic disease or GI loss (globulins also low)
- Prolonged portal hypertension and formation of secondary collateral circulation