CGM Versus FGM; or, Continuous Glucose Monitoring Is Not Flash Glucose Monitoring

J Diabetes Sci Technol. 2015 Sep 1;9(5):947-50. doi: 10.1177/1932296815603528. Print 2015 Sep.


It remains to be seen as to what share of the market FGM will achieve if the manufacturer can supply any amount desired.Will a significant portion of the glucose monitoring market then be taken over by FGM? The availability of FGM as anew option for glucose monitoring can basically be evaluated positively and it does indeed clearly show the benefit of“more information” on the glucose trend. The relatively low price for glucose monitoring using FGM and the unusual market introduction (not first via the National Association of Statutory Health Insurance Funds, as was the case with CGM) have given increased attention to the use of more glucose information. It will likely take a certain amount of time before other providers are able to bring different FGM systems to the market.The option of coupling a CGM system with an insulin pump offers the perspective of an automated insulin application,that is, a closed-loop system. Such systems are currently being tested under everyday conditions, although it is not possible to predict when they will actually reach the market.There are, however, such couplings where algorithms are responsible for shutting off insulin delivery when the glucose concentration reaches a defined level or if it will be reached in the foreseeable future. This significantly helps prevent hypoglycemia. These options are only available with CGM. The aim of this commentary is to present the differences between CGM and FGM, including the advantages and disadvantages of both approaches. We see significant benefits in both options based on the different positioning of the approaches and the different user groups.

Keywords: blood glucose measurement; continuous glucose monitoring; glucose sensors; metabolic control.

Publication types

  • Editorial

MeSH terms

  • Blood Glucose / analysis*
  • Blood Glucose Self-Monitoring / instrumentation*
  • Diabetes Mellitus, Type 1 / blood*
  • Diabetes Mellitus, Type 1 / drug therapy
  • Humans
  • Hypoglycemia / blood*
  • Hypoglycemia / chemically induced
  • Hypoglycemia / prevention & control
  • Insulin / adverse effects
  • Insulin / therapeutic use*
  • Insulin Infusion Systems


  • Blood Glucose
  • Insulin