A lancing device is a specialized, spring-loaded medical instrument engineered to hold a tiny, sterile needle, known as a lancet. Its purpose is to perform a quick, controlled puncture of the skin to obtain a small capillary blood sample, which is most often used for monitoring blood glucose levels. The device controls the precise depth of the needle penetration, minimizing discomfort while ensuring a sufficient volume of blood is collected for accurate testing. Proper technique in using this tool is important for both comfort and the reliability of the resulting diagnostic reading.
Preparing the Lancing Device
Before taking a sample, wash hands thoroughly with soap and warm water, followed by complete drying. This hygiene step helps prevent the introduction of contaminants into the puncture site and removes any sugar residue that could skew a glucose reading. Prepare the lancing device by twisting off the end cap and inserting a brand-new, sterile lancet firmly into the holder.
After seating the lancet, twist off the protective cap to expose the needle; save this cap for later safe disposal of the used needle. Replace the device cap, taking care not to touch the exposed tip. A mechanism on the lancing device, often a dial, allows for the adjustment of the penetration depth. Setting the depth appropriately reduces pain and is gauged by skin thickness. Lower settings (e.g., 1-2) are suitable for thin skin, and higher settings (e.g., 4-5) are necessary for thicker or calloused skin. Finally, arm the device by pulling back a slide or barrel until a click is heard, indicating it is ready to fire.
Step-by-Step Guide to Obtaining a Sample
The most reliable site for obtaining a blood sample is the fingertip, specifically the sides rather than the sensitive central pad. It is beneficial to rotate lancing sites across different fingers and across the sides of the same finger to prevent the development of calluses or soreness. Prior to lancing, gently massaging the finger from the base toward the tip or briefly warming the hands encourages blood flow to the capillaries, which helps ensure an adequate sample size.
With the device prepared and the chosen site ready, press the lancing device firmly against the side of the fingertip. Hold the device perpendicular to the finger and press down until the cap makes full contact with the skin. To activate the spring mechanism, press the release button, which rapidly drives the lancet into the skin and immediately retracts it. This rapid motion makes the process less painful than a slow, manual poke.
After the puncture, gently massage the finger from the palm toward the tip to encourage a round drop of blood to form. Avoid squeezing too aggressively, as this can force tissue fluid (interstitial fluid) into the sample, which may dilute the blood and lead to an inaccurate reading. If required, use a clean piece of gauze or a tissue to wipe away the first drop of blood. The second drop is considered a more pure capillary sample and should be the one collected by the test strip.
Post-Use Safety and Disposal
Once the sample has been collected, apply pressure to the puncture site with a clean tissue or cotton ball until any bleeding stops. Never reuse a lancet, as the tip dulls instantly upon first use, causing greater pain and increasing the risk of infection. Reusing lancets can also potentially introduce contaminants into the device or the skin.
The used lancet must be safely removed from the device immediately after testing. This is typically done by removing the device cap and using the ejector mechanism or by safely recapping the needle with the protective cap that was saved earlier. The lancet is classified as a sharp biohazard and must not be thrown into the regular household trash. Instead, all used lancets must be placed into a designated, puncture-resistant sharps container.
If an FDA-cleared sharps container is unavailable, a heavy-duty plastic container, such as an empty laundry detergent bottle with a screw-on lid, can serve as a temporary alternative. When the container is approximately three-quarters full, seal it securely and dispose of it according to local community guidelines, which often involve drop-off sites or mail-back programs.