Types of Drainage From a Surgical Wound

If you or a loved one has had surgery recently, the surgical incision site is likely the cause of much worry. While it is important to pay attention to the wound and to properly care for it, the sight of drainage can be anxiety-inducing, often needlessly.

Here is the good news: drainage from a wound can be alarming, but is not necessarily a problem, or even abnormal. In fact, drainage is often expected after surgery.

While it can be a very intimidating thing to have to take care of a surgical incision, for yourself or for a loved one, don't be alarmed just because the wound has drainage. Drainage does not necessarily mean you have an emergency or an infection on your hands.

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 by keeping the site clean. Preventing infection is always easier than treating an infection, especially since simple steps like proper hand washing are so effective. Keeping an eye out for early signs of infection is also important, as the earlier infection is identified the faster it can be treated, which reduces healing time.

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

Types of Normal Wound Drainage

Clear 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 to 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.

Mostly Clear/Tinged With Blood/Pink: serosanguinous drainage is a thin, watery drainage that is composed of both blood and serum. This discharge may appear slightly pink from the small number of 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.

Types of Abnormal Wound Drainage

Bloody/Sanguineous drainage: this is an abnormal wound drainage that typically has a larger amount of blood present than in serosanguinous (blood tinged) drainage. This bloody drainage is not typical of a healing wound and may indicate that the wound hasn't been treated gently enough during incision care, the patient is being too active too quickly after surgery or another type of stress is affecting the incision site. Report this type of drainage to your surgeon.

Mostly/all blood: hemorrhage is the term for severe bleeding from a wound that 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. In terms of drainage, hemorrhage is pure blood or nearly all blood. Seek treatment immediately.

Colorful Drainage: purulent drainage, better known by the common name of pus, is not a normal finding in an incision. This type of drainage can be a variety of colors, including white, yellow, grey, green, pink, and brown. Assume that this type of drainage is a sign of infection until proven otherwise. Color alone does not indicate infection, but a change from clear drainage to colorful drainage should be reported to the surgeon.

Foul Smelling Drainage: in addition to being a variety of colors, purulent (pus) discharge may also have unpleasant or foul smells. While this smell is not always present, it is typical with this type of infection.  Foul smelling discharge should not be ignored as it is never considered normal. Clear discharge with a foul odor should be considered a sign of infection until proven otherwise.

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.

Drainage With an Odor

Drainage that is normal and expected does not typically have a significant odor. Foul smelling drainage, or drainage that is notably odiferous—foul or otherwise—is not typical and may require treatment. Healthy drainage doesn't usually smell much at all, likewise, a healthy incision doesn't typically have much of an odor. 

A Word From Verywell

It can be a nerve-wracking thing, having a surgical wound, but that doesn't mean there is something to worry about. Normal wounds have normal drainage—it's clear or there is a little bit of blood or color—and it seems to get better day after day, or at least week after week. Abnormal wounds look angry and have angry drainage. They get worse—more tender, more drainage, more swelling—and they also feel worse most of the time.

Sometimes these angry wounds get worse quite quickly, and when that happens there is no denying the need for medical intervention. Trust your instincts and call your medical provider in this case.

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Article Sources
  • Advance For NPs and PAs. Wound Exudate: An Influential Factor In Healing.