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Serosanguineous

What Is It, Appearance, and More

Author: Ali Syed, PharmD

Editors: Ahaana Singh, Ian Mannarino, MD, MBA

Illustrator: Jillian Dunbar

Copyeditor: David G. Walker


What is serosanguineous fluid?

Serosanguineous fluid is a type of wound drainage, or exudate, secreted by an open wound in response to tissue damage. As part of the wound healing process, it is common for open wounds to secrete a certain amount of exudate. However, the quantity and appearance of the drainage is dependent on the type of tissue damage. The presence of serosanguineous fluid is usually indicative of damage to capillaries, which are the smallest blood vessels in the body. Capillaries can commonly become injured during wound care, such as when a wound dressing is being changed.

Serosanguineous fluid typically presents during the inflammatory stage of the wound healing process as a by-product of dilated blood vessels. During the inflammatory stage of wound healing, damaged cells will release inflammatory molecules to attract immune cells to the site of injury. This type of drainage is a sign of healing, and it is not usually a cause for concern when it appears in normal amounts.

Serosanguineous fluid is the most common type of exudate secreted by wounds in comparison to serous, sanguineous, and purulent drainage. Serous drainage is a clear, thin, and watery exudate that typically appears during the inflammatory stage of wound healing. A small amount of exudate is normal, while a large amount of exudate can represent a high bioburden count or an elevated number of potentially harmful bacteria living on a non-sterilized surface, which may represent infection. Sanguineous drainage constitutes fresh blood that is typically produced from deep wounds during the inflammatory stage of wound healing. Outside of this stage of wound healing, sanguineous drainage may indicate wound trauma and damaged capillaries. Continuous sanguineous drainage from a wound may also be a sign of a hemorrhage, which reflects damage to an artery or vein. This is known as hemorrhagic drainage. Lastly, purulent drainage typically secretes from infected wounds and consists of white blood cells, dead bacteria, and damaged cells.

What does serosanguineous mean?

Serosanguineous refers to an exudate composed of red blood cells and serous fluid, known as blood serum. Blood is composed of plasma, red blood cells, white blood cells, and platelets. Blood serum is a clear to pale yellow watery fluid found in the body, particularly in the spaces between organs and the membranes that enclose them.

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What does serosanguineous drainage look like?

Serosanguineous drainage is typically thin and watery with a light red or pink hue, which is a direct consequence of the blood cells that are present in the serum. In some cases, if there are very few red blood cells in the serum, the color of serosanguineous drainage may appear a pale yellow color.

Is serosanguineous drainage a sign of infection?

Serosanguineous drainage itself is not a sign of infection. However, purulent drainage, which appears to be slightly more opaque and thicker than serous drainage, may be a sign of infection. Purulent drainage, characterized by a milky appearance and thick consistency, is a strong indicator of an infected wound. Purulent drainage may be white, gray, green, or yellow in color and is often associated with a foul odor as it is composed of dead bacteria, viruses, white blood cells, and inflammatory cells. As a wound infection worsens, the amount of purulent discharge may also worsen in appearance and volume.

What are the most important facts to know about serosanguineous?

Serosanguineous drainage is the most common type of wound drainage secreted by an open wound in response to tissue damage. It is a thin and watery fluid that is pink in color due to the presence of small amounts of red blood cells. The presence of serosanguineous drainage is a normal occurrence, which usually appears during the inflammatory stage of the wound healing process and typically represents damage to capillaries.

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Related links

Skin anatomy and physiology
Wound healing
Burns
Integumentary: Applying dressings and bandages
Inflammation

Resources for research and reference

Adderley, U. (2010). Managing wound exudate and promoting healing. British Journal of Community Nursing, 15(3), S15-S20. DOI: 10.12968/bjcn.2010.15.sup1.46907 

Advanced Tissue (2014). Exploring the Various Types of Wound Drainage. Wound Care. Retrieved May 2nd 2021 from: https://advancedtissue.com/2014/08/exploring-various-types-wound-drainage/

Advanced Tissue (2014). Common Types of Wound Drainage. Wound Care. Retrieved May 2nd, 2021, from: https://advancedtissue.com/2016/03/common-types-of-wound-drainage/

Andronaco, L. (2016). Wound Exudate: Assessment and Management Strategies. Wound Source. Retrieved May 3rd, 2021, from: https://www.woundsource.com/blog/wound-exudate-assessment-and-management-strategies

Cutting, K. (2003). Wound exudate: Composition and functions. British Journal of Community Nursing, 8(9 Suppl), S4-S9. DOI: 10.12968/bjcn.2003.8.sup3.11577 

Johnson, J (2018). Serosanguineous drainage: Is it normal? In Medical News Today. Retrieved May 4th, 2021, from: https://www.medicalnewstoday.com/articles/320765

Whitlock, J. (2020). Types of Drainage from a Surgical Wound. In Very Well Health. Retrieved May 3rd, 2021, from: https://www.verywellhealth.com/types-of-drainage-from-a-surgical-wound-3156837