The reason is that originally spectroscopy and spectroscopic equipment was too large and expensive to be effective for self-use.

A patent was applied for in 1994 and approved in 1996. Diabetes Test Strips and the History Behind Them Diabetes test strips have made it possible for individuals with diabetes to manage their illness on their own. The scale was written on a chart and it involved simply matching. When diabetes test strips were first used, the strips would change color due to a chemical reaction between the chemicals in the blood and the chemicals on the strip.

Originally, it was difficult for individuals to self-test because of the level of equipment that was necessary to locate the analytes within human blood originally. The inventor of these strips is listed as Nicola J. The current diabetes test strips that most people are used to seeing and used to using are based off the detection of what is called blood analyte levels. It is a revolutionary product that has gone from giving only a general range to being able to give exact numbers allowing people to control their diabetes and take back their lives.

The color would indicate the glucose level within the blood.