Influence of repetitive finger puncturing on skin perfusion and capillary blood analysis in patients with diabetes mellitus

Background: Frequent puncturing of fingers to check blood glucose in patien ts with type 1 diabetes might alter skin perfusion and, hence, influence th e representativeness of the blood sample. We investigated the influence of repetitive puncturing on skin microcirculatory perfusion using laser Dopple r fluxmetry and on the preanalytical phase of capillary blood analysis for small molecules (glucose) and large particles (cholesterol). Methods: In 49 patients with long-standing (mean, 21 years) type 1 diabetes , with a mean puncture frequency of three times daily for a mean duration o f 13 years, laser Doppler skin perfusion was measured in a finger at a freq uently punctured site and compared with a similar site of another finger of the same hand, which was never punctured. In the supine position with the hand level with the heart, resting flux (RF), peak flux (PF), and the micro circulatory reserve capacity (MRC; PF - RF) were assessed. Subsequently, bl ood samples for capillary whole blood glucose and cholesterol analyses were taken from the same sites. Results: No significant differences were found between the puncture and con trol sites in mean RF (2.3 vs 2.0 V; P = 0.14, paired-samples t-test), PF ( 3.3 vs 3.1 V; P = 0.24), MRC (1.0 vs 1.0 V; P = 0.65), glucose (10.2 vs 10. 2 mmol/L; P = 0.69), or cholesterol (5.1 vs 5.2 mmol/L; P = 0.26). Power ca lculation for a RF of 2.0 V and the SD and n of this study indicate a power (beta) of 80% to detect a 25% change in RF at P <0.05. Conclusions: Repetitive finger puncturing in diabetics appears not to injur e local skin microcirculatory perfusion nor to influence results of capilla ry blood analysis for glucose and cholesterol. (C) 1999 American Associatio n for Clinical Chemistry.