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 per microliter) 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

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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 < 23 > 0.6[2] or > 23[3]
Cholesterol content < 45 mg/dL > 45
Radiodensity on CT scan 2 to 15 HU[5] 4 to 33 HU[5]

There is an important distinction between transudates and exudates. Transudates are caused by disturbances of hydrostatic or colloid osmotic pressure, not by inflammation. They have a low protein content in comparison to exudates and thus appear clearer.[6]

Levels of lactate dehydrogenase (LDH)[7] or a Rivalta test can be used to distinguish transudate from exudate.[citation needed]

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.[citation needed]

Pathology

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The most common causes of pathologic transudate include conditions that:[citation needed]

See also

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References

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  1. ^ a b The University of Utah • Spencer S. Eccles Health Sciences Library > WebPath images > "Inflammation".
  2. ^ a b Heffner J, Brown L, Barbieri C (1997). "Diagnostic value of tests that discriminate between exudative and transudative pleural effusions. Primary Study Investigators". Chest. 111 (4): 970–80. doi:10.1378/chest.111.4.970. PMID 9106577.
  3. ^ a b Light R, Macgregor M, Luchsinger P, Ball W (1972). "Pleural effusions: the diagnostic separation of transudates and exudates". Ann Intern Med. 77 (4): 507–13. doi:10.7326/0003-4819-77-4-507. PMID 4642731.
  4. ^ Roth BJ, O'Meara TF, Gragun WH (1990). "The serum-effusion albumin gradient in the evaluation of pleural effusions". Chest. 98 (3): 546–9. doi:10.1378/chest.98.3.546. PMID 2152757.
  5. ^ a b Cullu, Nesat; Kalemci, Serdar; Karakas, Omer; Eser, Irfan; Yalcin, Funda; Boyaci, Fatma Nurefsan; Karakas, Ekrem (2013). "Efficacy of CT in diagnosis of transudates and exudates in patients with pleural effusion". Diagnostic and Interventional Radiology. 20: 116–20. doi:10.5152/dir.2013.13066. ISSN 1305-3825. PMC 4463296. PMID 24100060.
  6. ^ The University of Utah • Spencer S. Eccles Health Sciences Library; WebPath images "Inflammation".
  7. ^ "IM Quiz: Pleural Adenocarcinoma". Archived from the original on 2008-09-16.