Types of Drainage from a Surgical Wound

Does Drainage Mean My Surgical Incision Is Infected?

Cleaning wounds after surgery
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Help, my surgical incision has drainage! Should a wound have drainage or does it mean an infection is present?


Hold on! It can be a very scary thing to have to take care of a surgical incision, for yourself or for a loved one, but drainage doesn't necessarily mean you have an emergency or even an infection on your hands. Repeat after me: some drainage can be normal!

Truly, some drainage can be completely normal and just means your wound is healing normally.

In some cases, drainage can be a sign of infection, but for most people, good wound care will prevent an infection. Preventing infection is key, using simple steps like proper hand washing and keeping an eye out for early signs of infection.

Exudate, which is the medical term for drainage, comes in a variety of forms. The way the drainage looks indicates whether the wound is healing normally or if it needs medical attention.

Types of Normal Wound Drainage

Serous drainage is clear and may be slightly yellow or colorless in appearance. It is thin and watery and may make a bandage wet without leaving a stain of color. Serous exudate, or discharge, is normal from a wound in the early stages of healing, typically in the first 48-72 hours after the incision is made.

While serous fluid is normal in small amounts, large amounts of this clear fluid leaving the incision line should be reported to the surgeon.

In some cases, serous fluid can actually weep from the skin, even where there is no trauma or incision. This typically happens when the person has severe pitting edema due to a medical condition or after massive amounts of fluid are given, such as during treatment for severe trauma.

This is a thin, watery drainage that is composed of both blood and serum.

This discharge may appear slightly pink from the red blood cells that are present. This is normal in the early stages of healing, as the blood is present in small amounts. It is important to keep in mind that a very small percentage of blood in the fluid can make serum appear pink.

  • Serous Drainage: Clear, watery and no blood present.
  • Serosanguinous Drainage: Mostly clear but is pink from the small amount of blood present.  

Types of Abnormal Wound Drainage

This type of drainage has a larger amount of blood present than in serosanguinous drainage. This drainage is not typical of a healing wound and may indicate that the wound hasn't been treated gently enough during incision care, or being too active too quickly after surgery. This type of drainage may also be in wounds that require vigorous cleansing, such as a wet to dry dressing change that is intended to remove dead tissue from the incision line.

This type of drainage, or drainage that is increasingly bloody with no clear cause, should be reported to the surgeon.

Severe bleeding from a wound can be life-threatening, depending on the amount of blood loss, how difficult the bleeding is to control, how long the bleeding goes unchecked, and other injuries. The term hemorrhage refers specifically to blood being lost at a rapid rate.

Medical attention is an absolute necessity for treating hemorrhages, and may include blood transfusions and fluid resuscitation.

  • Sanguinous Drainage: Bloody drainage, but not all blood.  Some clear fluid is present, thinning the mixture. 
  • Hemorrhage: A large amount of pure blood, seek medical attention.
  • Purulent Discharge (Pus):  This discharge is often smelly, comes in unusual colors such as green and creamy yellow or white, and it is a sign of infection. Seek medical attention.

Better known by the common name of pus, purulent drainage is not a normal finding in an incision. This type of exudate can be a variety of colors, including white, yellow, grey, green, pink, and brown.

In addition to being a variety of colors, purulent discharge may also have unpleasant or foul smells. While this smell is not always present, it is typical with this type of infection.

Any signs of infection, including pus, should be reported to the surgeon immediately.

Amount of Wound Drainage

While the type of drainage is important, the amount of drainage may be more important, depending upon the type. For example, if there is a small amount of bleeding from a wound, it may not be alarming, but blood gushing from a wound, known as hemorrhage, is a life-threatening condition.

In general, the amount of discharge, and the amount of blood in the discharge should decrease in the days following surgery. More discharge is expected in the first few days following surgery; after that, most wounds will typically have less discharge with less blood in it until there is no discharge whatsoever and the wound has completely closed.


Advance For NPs and PAs. Wound Exudate: An Influential Factor In Healing. Accessed May 2012.http://nurse-practitioners-and-physician-assistants.advanceweb.com/article/wound-exudate.aspx?CP=2

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