Computing the surveillance error grid analysis: procedure and examples

J Diabetes Sci Technol. 2014 Jul;8(4):673-84. doi: 10.1177/1932296814539590. Epub 2014 Jun 13.


The surveillance error grid (SEG) analysis is a tool for analysis and visualization of blood glucose monitoring (BGM) errors, based on the opinions of 206 diabetes clinicians who rated 4 distinct treatment scenarios. Resulting from this large-scale inquiry is a matrix of 337 561 risk ratings, 1 for each pair of (reference, BGM) readings ranging from 20 to 580 mg/dl. The computation of the SEG is therefore complex and in need of automation. The SEG software introduced in this article automates the task of assigning a degree of risk to each data point for a set of measured and reference blood glucose values so that the data can be distributed into 8 risk zones. The software's 2 main purposes are to (1) distribute a set of BG Monitor data into 8 risk zones ranging from none to extreme and (2) present the data in a color coded display to promote visualization. Besides aggregating the data into 8 zones corresponding to levels of risk, the SEG computes the number and percentage of data pairs in each zone and the number/percentage of data pairs above/below the diagonal line in each zone, which are associated with BGM errors creating risks for hypo- or hyperglycemia, respectively. To illustrate the action of the SEG software we first present computer-simulated data stratified along error levels defined by ISO 15197:2013. This allows the SEG to be linked to this established standard. Further illustration of the SEG procedure is done with a series of previously published data, which reflect the performance of BGM devices and test strips under various environmental conditions. We conclude that the SEG software is a useful addition to the SEG analysis presented in this journal, developed to assess the magnitude of clinical risk from analytically inaccurate data in a variety of high-impact situations such as intensive care and disaster settings.

Keywords: blood glucose monitoring; error grid analysis; hyperglycemia; hypoglycemia; meter errors.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Blood Glucose / analysis
  • Blood Glucose Self-Monitoring / statistics & numerical data*
  • Diabetes Mellitus / blood*
  • Humans
  • Hyperglycemia / blood
  • Hyperglycemia / epidemiology
  • Hypoglycemia / blood
  • Hypoglycemia / epidemiology
  • Reagent Strips
  • Reference Values
  • Risk Assessment
  • Software


  • Blood Glucose
  • Reagent Strips