Stanley Kim

Keck School of Medicine, University of Southern California, 1148 San Bernardino Road Suite 300, Upland, CA, USA.  

Abstract

A new lancet with an extremely small needle (0.15 mm diameter and 0.75 mm length) mounted on a small pedestal was tested in diabetic patients for blood glucose measurement in a randomized clinical study. A total of 37 diabetic patients were enrolled for the study. A pain scale categorized from 0 to 3 was created to measure the intensity of puncture pain which was explained to patients before testing. The patients’ fingers were punctured with their own old style lancets at least 1 hour before the punctures by the new lancets, and puncture pains recorded according to the pain scale. All patients tested with the new lancet reported no pain and recorded the puncture pain as scale 0. Among the total 37 patients tested with their old style lancets, 2 patients (5.40%) reported no pain and recorded the pain as scale 0, thirteen patients (35.14%) recorded as scale 1, 16 patients (43.24%) as scale 2, and 6 patients (16.22%) as scale 3. The average pain scale of the patients who used old style lancets was 1.702 with the standard error 0.133. The chi-square goodness-of-fit test shows that the proportion of the pain scales comes from the claimed distribution with unequal frequencies, and chi-square tests for independence indicate that neither sex nor age of the sample patients is related to the pain scales.
The paired t-test to test the existence of any difference in pain levels between the new lancet and the old style lancet showed; t = 1.702/0.133 = 12.796 with p-value < 0.005 (df = 36). The average pain level from the old style lancet is significantly higher than from the new lancets. Pain-free needle puncture was achieved by limiting the puncture depth to less than 0.75 mm with a thin needle with a 0.15 mm diameter. By allowing patients to see the new lancets before testing, psychological pain anticipation was minimized as the very thin and short needle is visually less intimidating. With a pain free puncture, better compliance and improved subsequent glucose levels may be achieved.