Lancing, in a medical context, refers to making a small incision or puncture into the skin or tissue using a sharp instrument. This procedure is performed either to access a fluid-filled cavity for drainage or to obtain a small fluid sample for testing. The term describes a specific technique used in various clinical settings, ranging from minor, routine diagnostic tests to more involved therapeutic interventions.
Lancing for Therapeutic Incision and Drainage
The most involved application of lancing is the minor surgical procedure known as Incision and Drainage (I&D). This technique is the primary treatment for localized collections of pus, such as an abscess, furuncle (boil), or cyst, that have become walled off by the body’s immune system. These infected pockets create significant pressure and pain as they accumulate material beneath the skin.
The procedure begins with the healthcare provider thoroughly cleaning the area with an antiseptic solution, like chlorhexidine or povidone-iodine, and administering a local anesthetic to minimize discomfort. A field block injection is often used to numb the tissue surrounding the abscess cavity, rather than injecting directly into the inflamed area. Once the site is desensitized, a sterile scalpel is used to make a linear cut over the center of the mass.
This controlled incision allows the trapped pus and fluid to be released, which immediately relieves the painful pressure. After the initial drainage, a blunt instrument, such as a curved hemostat, is introduced into the cavity to carefully break up any internal compartments, known as loculations, that might be trapping residual infected material. The wound cavity is then flushed, or irrigated, with a sterile solution like normal saline to wash out remaining debris.
For abscesses, particularly larger ones, the wound may be packed with a strip of sterile gauze to prevent the skin edges from closing prematurely. This material acts as a wick, ensuring that any subsequent fluid continues to drain out as the tissue heals from the inside out. This method of healing is referred to as secondary intention, which is the preferred way to close an infected wound.
Lancing for Diagnostic Blood Sampling
Lancing also describes the rapid, superficial puncture of the skin used to collect small volumes of capillary blood for diagnostic testing. This procedure utilizes a specialized, sterile instrument called a lancet, which is often housed within a spring-loaded lancing device to control the depth and speed of the puncture.
The most common application is for routine blood glucose monitoring, where a tiny drop of blood is collected from the fingertip to check blood sugar levels, which is a daily necessity for individuals managing diabetes. The lancing device often has adjustable depth settings, allowing the user to customize the penetration depth based on skin thickness and the required blood volume. The puncture is performed on the side of the fingertip to reduce discomfort.
Lancing is also employed for other point-of-care diagnostics, such as cholesterol and hemoglobin checks, which only require a few microliters of blood. A specific form of this procedure is the heel stick, used to collect blood samples from newborns for screening tests, including those for phenylketonuria and congenital hypothyroidism. In infants, the puncture depth is strictly regulated, not exceeding 1.0 millimeter, to avoid injury to the heel bone.
Preparation, Aftercare, and Potential Complications
Patient preparation for any lancing procedure centers on hygiene and open communication with the healthcare provider. For both I&D and diagnostic sampling, the skin must be meticulously cleaned with an antiseptic agent before the instrument is introduced to prevent the introduction of surface bacteria. Patients should inform their provider about any allergies, especially to local anesthetics, or any medication use that might affect blood clotting.
I&D Aftercare and Complications
After an Incision and Drainage procedure, detailed aftercare is necessary for proper wound healing. If the wound was packed with gauze, the patient is usually instructed to return to the clinic within 24 to 48 hours for its removal, or they may be taught how to change the dressing themselves. The wound must be kept clean and dry, and patients are often advised to perform warm soaks to encourage continued drainage and promote the formation of healthy tissue.
The focus of I&D aftercare is monitoring the site for signs of recurrent infection or poor healing. Complications, though not frequent, can include the development of a surgical site infection, which may manifest as increasing pain, excessive redness, fever, or foul-smelling discharge from the wound. While some scarring is expected due to the nature of the incision and healing by secondary intention, excessive bleeding or nerve irritation around the site should be reported immediately.
Diagnostic Lancing Aftercare
After a diagnostic blood lancing, aftercare is minimal, usually involving applying light pressure to the puncture site until the small amount of bleeding stops. The risk of complications is low, but includes localized bruising, persistent bleeding, or a superficial infection. Proper disposal of the used lancet is necessary to prevent accidental needle-stick injuries to others.