Alternate Site Glucose Testing: Close, but Not Close Enough?

Purpose: Monitoring of blood glucose in the perioperative diabetic patient requires fingerstick blood sample. Suggestions from patients regarding less pain with alternative site testing (AST) prompted initial study comparing standard fingerstick with AST. Previous study indicated AST to be less painful compared with standard method, with little difference in glucose values (R=.98). Though statistically significant, change from standard practice to AST requires R=.99 per institutional recommendations. In an effort to support previous findings, a replication study was conducted with a power analysis generating a larger volume of subjects. The hypothesis, “Would an increased sample size support similar findings from previous study and also a higher R?”

Methods: Prospective Convenience study - Two methods of obtaining blood glucose sample were studied. Fingerstick compared with sample from palm of dominant hand. Eligible patients were randomized. Variables controlled by decreasing number of research team members from six data collectors to two, scripting, and blood glucose monitoring competency were created. Time between palm stick and fingerstick was limited to two minutes.

Results: Phase two results reinforced findings from original study. On average, participants rated pain about one category lower than standard site (Mean diff – 1.29(0.15)). Blood glucose results also similar to original study (partial correlation = 0.98).

Conclusion: Findings support less pain experienced with AST compared with standard site. Further analysis still needed to confirm accuracy of AST blood glucose values compared to standard site. Value of R=.98 support AST as alternative method for glucose monitoring however, R=.99 required for practice change. Investigation into vendor and product availability which support AST as alternative to standard fingerstick to be explored. In addition, consider conducting same-subject fingerstick blood glucose comparison study. Though statistically significant findings related to less pain and proven accuracy of AST compared to fingerstick glucose were supported, barriers to implementation of change in practice include funding and regulatory constraints.