A lancing device is a spring-loaded tool used for capillary blood sampling, primarily for monitoring blood glucose levels in individuals managing diabetes. This device holds a small, sterile needle, known as a lancet, and controls its penetration depth and speed into the skin. Using the device correctly ensures a consistent method for obtaining the small blood drop needed for testing.
Preparing the Device and Testing Site
The process begins by thoroughly washing your hands with warm water and soap, which helps to minimize the risk of infection while also improving blood flow to the fingertips. After drying your hands completely, remove the cap from the lancing device to access the lancet port. You must insert a new, unused sterile lancet into the device for every test to maintain sharpness and sterility.
Once the lancet is securely in place, twist off the protective cover on the lancet tip before the device cap is reattached. The final step is to “cock” or prime the device. This involves pulling back a plunger or sliding a barrel until a click is heard, setting the spring mechanism for the rapid puncture when the release button is pressed.
Detailed Lancing Procedure
With the device prepared, select a puncture site, preferably on the side of a fingertip, as this area has fewer nerve endings than the sensitive central pad. Press the lancing device firmly against the chosen site, ensuring full contact with the skin, which helps to stabilize the tissue during the puncture. Activating the release button triggers the spring mechanism, causing the lancet to quickly penetrate and immediately retract from the skin.
After the puncture, remove the device and wait for a blood droplet to form naturally. If a drop does not appear, gently massage or “milk” the finger from the base toward the tip to encourage blood flow. The first drop of blood should be wiped away, especially if an alcohol swab was used, because this initial sample may contain tissue fluid that dilutes the blood and affects test accuracy. A clean, second drop of blood is then applied to the test strip.
Maximizing Comfort and Sample Quality
To find the ideal balance between comfort and sample volume, most modern lancing devices feature adjustable depth settings. These settings allow you to customize the penetration depth to accommodate different skin thicknesses, with higher numbers indicating a deeper stick. A good practice is to begin with the shallowest setting and increase the depth only until a sufficient blood sample is consistently obtained.
For those who test frequently, rotating between different fingers prevents soreness and callus buildup in one area. Some individuals may also use alternative testing sites (AST) like the palm or forearm, which often have fewer pain-sensing nerve endings than the fingertips. However, glucose measurements from these alternate sites may lag behind fingertip values by up to 20 minutes, making them unsuitable when blood sugar levels are changing rapidly, such as after a meal or during exercise.
Proper Lancet Disposal
Safely disposing of the used lancet is crucial. Never attempt to reuse a lancet, as the tip dulls quickly, causing increased pain and potential tissue damage. After testing, carefully remove the used lancet from the device, often by using a built-in ejector mechanism or by recapping the exposed needle tip with the flat safety cover.
The used sharp must be immediately placed in a specialized, puncture-proof sharps container. If a commercial sharps container is unavailable, a heavy-duty plastic container, such as a laundry detergent bottle with a tight-fitting lid, can serve as a temporary alternative. Used lancets must never be thrown directly into household trash or recycling bins, as this poses a serious risk of injury to waste handlers.