Capillary blood glucose testing requires a drop of blood to measure sugar levels, necessary for managing diabetes and making treatment decisions. Performing the fingerstick incorrectly can lead to discomfort or inaccurate readings. Finding the right technique and location is important for minimizing pain and ensuring reliable results. Consistent, less painful testing makes it easier to maintain the schedule needed for insight into glucose control.
Selecting the Best Testing Site
The choice of finger for blood glucose testing is not arbitrary, as anatomy dictates both comfort and sample quality. The best fingers for this procedure are generally the middle, ring, and pinky fingers, as they are used less frequently in daily activities. Using these fingers helps preserve the sensitivity of the thumb and index finger, which are constantly relied upon for tasks like writing or gripping.
Avoid the index finger and thumb because the skin is often thicker and more callused from overuse, requiring a deeper, more painful stick. The center pad of any fingertip contains a high concentration of nerve endings, making a puncture significantly more sensitive. Therefore, the most recommended spot for a fingerstick is the side of the fingertip, slightly off-center.
Testing on the sides of the fingers is less painful due to fewer nerve endings compared to the center pad. This area also has adequate capillary blood supply, ensuring a good sample. Rotating between the six to eight testing sites (the sides of the middle, ring, and pinky fingers on both hands) is an effective strategy to prevent tenderness and the buildup of calluses.
Essential Technique for Accurate Results
Proper preparation is important for encouraging blood flow and minimizing contamination before the fingerstick. Wash hands thoroughly with warm, soapy water; the warm water helps dilate blood vessels, making it easier to draw a sample. Residue from food or hand creams can mix with the blood and lead to a falsely elevated or inaccurate glucose reading.
Once the hand is clean and dry, adjust the lancet device’s depth setting to be as shallow as possible while still yielding a sufficient drop of blood. A deeper setting may be needed for thicker skin, but starting shallow reduces the chance of unnecessary pain. Prick the side of the chosen fingertip quickly to minimize sensation.
Wipe away the first drop of blood that appears after the puncture with a clean piece of gauze or cotton. This initial drop may contain tissue fluid or residual surface contaminants that can interfere with the test strip’s chemical reaction. Using the second, well-formed drop of blood provides a more concentrated and truer capillary blood sample for the most accurate result. To produce the second drop, apply only gentle pressure near the puncture site, avoiding aggressive squeezing or “milking” of the finger, which compromises accuracy.
Troubleshooting Common Issues
Even with the correct location and technique, a few common problems may arise during the testing process. One frequent issue is an insufficient blood sample, where the lancet does not produce a drop large enough to fill the test strip. If this occurs, try warming your hands again or letting your arm hang down for a minute to promote blood flow before attempting a new stick on a different site.
If you consistently find testing to be excessively painful, ensure you are rotating sites and sticking the sides of the fingertips, not the pads. If pain persists, slightly reducing the lancet device’s depth setting may be necessary to find the minimum penetration required for a sample. Overly callused fingers from long-term testing can also make obtaining a sample difficult and painful. If a particular finger has become hardened, switch to less-used fingers, such as the pinky, to allow the callused skin to soften over time.