Exudate vs Transudate: Difference and Comparison

Our lung system consists of two lungs. Both our lungs are covered by a double membrane called the pleural membrane. The space between the lungs and a pleural membrane is called pleural space.

A dysfunction in the human body may lead to accumulation of two types of fluid in the pleural space. These are called Exudate and Transudate. 

Key Takeaways

1. Exudate is a fluid that leaks out of blood vessels into the surrounding tissue, due to inflammation or injury.
2. Transudate is a fluid that passes through the walls of blood vessels due to an imbalance in hydrostatic and oncotic pressure.
3. Exudate is cloudy and contains high levels of protein and cells, while Transudate is clear and contains low levels of protein and cells.

Exudate vs Transudate

Exudate is a fluid rich in proteins and inflammatory cells produced as a result of inflammation or infection. Transudate is a low-protein fluid produced by changes in blood vessels, which can lead to accumulation in congestive heart failure, liver disease, and kidney disease.

Exudate is also referred to as pus. It is a fluid that leaks from the body’s blood vessels and accumulates in the tissues. This fluid leakage is made up or consists of proteins, plasma, cells, and other solid materials.

Exudates ooze or leak out via cuts from wounds or swollen areas of infection or inflammation. 

Transudate is a fluid forced out of the walls of blood vessels due to a lot of pressure in the veins and capillaries. The fluid is also called the filtrate of blood.

It escapes the blood vessels and accumulates as oedema near the body’s tissues. Oedema refers to a kind of swelling.

Comparison Table

Parameters Of Comparison	Exudate	Transudate
Appearance	The fluid, in this case, appears to be turbid and bloody.	The protein level in the liquid is more than 30 grams per litre.
Protein Level	The protein level in the liquid is more than 30 grams per litre.	The protein level in the liquid is more than 30 grams per liter.
Symptoms	The symptoms of exudate are: •Shortness of breath  •Chest pain  •Fast breathing	The symptoms of transudate are: •Difficult breathing •Cough  •Pleurisy or painful breathing
Cause	Exudate can be caused due to different kinds of pulmonary infections.	Transudate can be caused due to increased pulmonary capillary pressure.
Specific Gravity	The specific gravity of exudate is more than 1.015.	The specific gravity of a transudate is less than 1.015.

 What is Exudate?

Exudate is a turbid and bloody fluid that leaks through the blood vessels. The fluid leakage accumulates in the tissues of the body. The fluid also forms an inflammation which is called pus. 

The characteristics of an exudate:

• Cholesterol level – More than or equal to 1.2 Milli mole per litre.
• Protein level – More than or equal to 30 grams per litre.
• Glucose level – low amount of concentration.
• LD activity – More than 0.67 in concentration.
• Specific gravity – More than a concentration of 1.015. 

Exudate is caused due to several reasons. There are different causes for watery fluid (transudate) and protein-rich (exudate) fluid. Causes of protein-rich fluid are cancer, kidney failure, inflammatory disease, pneumonia, and pulmonary embolism.

Constituents of exudate are:

• Water 
• Electrolytes
• Proteins 
• Nutrients 
• White blood cells 
• Inflammatory mediators 
• Proteases 
• Microorganisms
• Growth factors 

Symptoms of exudate are: 

• Pain in the chest.
• Fast breathing.
• Painful breathing.
• Shortness of breath.
• Orthopnea (difficulty in breathing when lying down flat). 

Exudate leaks out of certain injured areas, infected areas, or inflated areas due to infections or wounds. It is called pus and is filled with protein fluid. A few examples of exudate are latex, resins, gums, and saps. 

What is Transudate?

Transudate is a pale, yellow, and quite clear fluid. It is referred to as a filtrate of blood. The increased pressure in the blood vessels causes this type of fluid leakage, which later accumulates in the tissues.

The characteristics of a transudate are:

• Cholesterol level – Lesser than 1.2 Milli mole per litre.
• Protein level – Lesser than 30 grams per litre.
• Glucose level – high amount of concentration.
• LD activity – Less than 0.67 in concentration.
• Specific gravity – Less than a concentration of 1.015. 

Transudate effusion is caused due to several various factors. One of the main factors in heart failure. The other common causes of watery fluid are cirrhosis, heart failure, post-open heart surgery, and pulmonary embolism.

Here are a few other common causes of transudate effusion:

• Nephritic syndrome.
• Myxedema.
• Constructive pericarditis.
• Superior vena cava obstruction.
• Peritoneal dialysis.

Symptoms of transudate fluid are: 

• Rough and dry cough.
• Trouble breathing.
• Pleurisy.
• Trouble in the chest area.
• Presence of oedema (swelling).

Constituents of transudate are:

• Macrophages
• Mesothelial cells
• Lymphocytes
• Watery solution 
• A few nucleated cells
• Protein 
• Cholesterol 
• Primary cells 

Transudate effusion refers to the fluid leaked into the space between the two membrane coverings of the lung. It has low protein concentration and fewer cells. It could lead to liver diseases and kidney diseases.

Main Differences Between Exudate and Transudate 

1. Exudate has a high level of protein, while on the other hand, the protein level in transudate is comparatively less. 
2. The cholesterol level in an exudate is more than 1.2 millimoles per litre, whereas the cholesterol level in a transudate is less than 1.2 millimoles per litre.
3. Exudate has a low glucose level while on the other hand, a transudate has a high glucose level.
4. Exudate witnesses a high LD activity, while the other hand, transudate witnesses a low LD activity.
5. Exudate appears to be bloody and turbid, while on the other hand, transudate is clear and yellowy.

References

1. https://www.magonlinelibrary.com/doi/abs/10.12968/bjcn.2003.8.Sup3.11577
2. https://thorax.bmj.com/content/56/11/867.abstract