Transudate
Transudate is extravascular fluid with low protein content and a low specific gravity (< 1.012). It has low nucleated cell counts (less than 500 to 1000 /microlit) and the primary cell types are mononuclear cells: macrophages, lymphocytes and mesothelial cells. For instance, an ultrafiltrate of blood plasma is transudate. It results from increased fluid pressures or diminished colloid oncotic forces in the plasma.
Transudate vs. exudate
| Transudate vs. exudate | ||
|---|---|---|
| Transudate | Exudate | |
| Main causes | ↑ hydrostatic pressure, ↓ colloid osmotic pressure |
Inflammation-Increased Vascular Permeability |
| Appearance | Clear[1] | Cloudy[1] |
| Specific gravity | < 1.012 | > 1.020 |
| Protein content | < 2.5 g/dL | > 2.9 g/dL[2] |
| fluid protein/ serum protein |
< 0.5 | > 0.5[3] |
| SAAG = Serum [albumin] - Effusion [albumin] | > 1.2 g/dL | < 1.2 g/dL[4] |
| fluid LDH upper limit for serum |
< 0.6 or < 2⁄3 | > 0.6[2] or > 2⁄3[3] |
| Cholesterol content | < 45 mg/dL | > 45 mg/dL[2] |
Levels of lactate dehydrogenase (LDH)[5] or a Rivalta test can be used to distinguish transudate from exudate.
Their main role in nature is to protect elements of the skin and other subcutaneous substances against the contact effects of external climate and the environment and other substances – it also plays a role in integumental hygiene.
Transudate usually appears more clear than exudate as it has low protein content.[6]
see also: Light's criteria for pleural effusions.
Pathology
The most common causes of pathologic transudate include: conditions that increase hydrostatic pressure in vessels, left ventricular heart failure, decrease in colloid oncotic pressure in blood vessels, cirrhosis (Cirrhosis leads to hypoalbuminism and decreasing of colloid oncotic pressure in plasma that causes edema), and Nephrotic syndrome (also due to hypoalbuminemia caused by proteinuria) Increased hydrostatic pressure: congestive heart failure. Decreased oncotic pressure : cirrhosis,nephrosis and malnutrition (hypoalbuminism)
See also
Exudate – extravascular fluid due to vessel alteration during inflammation (increased permeability, vascular constriction then dilation). This results in an extracellular fluid of high protein content, with cell debris present and high specific gravity (>1.020).
This is in contrast to transudate where the extracellular fluid is an ultrafiltrate of blood plasma and thus larger molecules such as proteins and cell debris are absent.
References
- ↑ 1.0 1.1 The University of Utah • Spencer S. Eccles Health Sciences Library > WebPath images > Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ The University of Utah • Spencer S. Eccles Health Sciences Library; WebPath images Lua error in package.lua at line 80: module 'strict' not found.
