Glucose Monitoring: Progress Throughout the Years

It always amazes me to think about how far diabetes treatment and management has come over the last nearly 100 years (since the discovery of insulin in 1921). While there is no cure yet, I am optimistic that life for those of you with this chronic condition, be it type 1 or type 2 diabetes, will continue to become more manageable.

With November being diabetes awareness month, what better time then now, to take a closer look at how glucose monitoring has evolved throughout the years? Self-monitoring of blood glucose has become a mainstay in diabetes self-care and for many of you is something that is done several times of day.

Measuring glucose in the urine

• 1841, 1850: Karl Trommer and Hermann von Fehling, respectively, developed the first clinical tests for measuring glucose in the urine¹
• 1907: Stanley Benedict came up with a method that simplified measuring glucose in the urine^1,2

Limitations of measuring glucose in the urine

• Glucose is not evident in the urine until glucose is significantly elevated ²
• Glucose in the urine is considered past information (i.e. not a reflection of the current glucose level) as it is the glucose level at the time the urine was made in the kidneys^1,2

Measuring glucose in the blood:

• 1913: Ivar Bang developed the first method to test glucose in the blood
• 1940’s to 1950’s: The Ames company developed an improved glucose test strip called the Clinistix (this test strip was originally made to test glucose in the urine and later to be found, by researcher Kohn, that it could also provide an approximate blood glucose level)³
• 1965: The first blood glucose test strip, the Dextrostix, was developed by the Ames research team³
• 1970’s to 1980’s: The first home blood glucose monitor, called the Ames Eyetone, became commercially available ²
• 1980’s and onward: Home blood glucose meters continued to evolve and improve. Improvements included: better accuracy, smaller meter size, smaller blood sample size, and the ability to store blood glucose history

Limitations of measuring glucose in the blood:

• Requires a finger poke that for many is painful
• Blood glucose only shows one moment in time and does not indicate the speed or direction of blood glucose

Measuring glucose in the interstitial fluid: 

Late 1990’s and early 2000’s: continuous glucose monitoring (CGM) devices made their entrance into the world of glucose monitoring. These devices measure glucose in the interstitial fluid which is the fluid surrounding the body cells. CGM devices can give glucose readings as frequently as every 5 minutes and additionally show the speed and direction glucose is headed.

Some of the highlights include:

• 1999: Medtronic gets FDA approval for the first physician-used CGM device ⁴
• 2004: Medtronic gets FDA approval for a patient-used CGM device ⁴
• 2006: Dexcom introduces its first CGM
• 2016: FDA approves the Dexcom G5 system “as a replacement to finger stick glucose testing for diabetes treatment decisions” ⁵
• 2017: Medtronic launches the world’s first hybrid closed loop system for type 1 diabetes.⁴ This system combines a CGM with an insulin pump, allowing for insulin adjustments based on CGM readings.
• 2017: Abbot launches Freestyle Libre flash CGM in the USA
• 2018: Senseonics introduces the first, FDA approved, implantable CGM. The Eversense CGM can be worn for up to three months.

Limitations of measuring glucose in the interstitial fluid:

• Lag time - Sensor glucose levels lag behind blood glucose levels. However this has significantly improved since CGM devices first became available.
• A small injection is required to place the sensor portion of the CGM just below the skin into the subcutaneous tissue.
• For the best results CGM devices should be worn consistently. Some people do not like the idea of always having to wear a device that reminds them of having diabetes.

Wow! What a journey it has been in the world of monitoring glucose. How do you monitor your glucose? Do you have any predictions for what the future will hold in terms of glucose monitoring? Please share your experiences and thoughts with type2diabetes.com.