An instantly available diagnostic aid and therapeutic guide for the rapid estimation of blood glucose concentration has been conspicuous by its absence. Previous attempts to meet this need by streamlining the usual time-consuming laboratory procedure have included those of Wilkerson and Heftmann1and Leech and Woodford,2as well as the use of Dextrotest, a simplified blood sugar test outfit. These attempts have not met widespread acceptance because they require special equipment that is cumbersome to operate. An indicator paper known as Tes-Tape is now being increasingly used by patients with diabetes for the detection of urinary glucose. The green-blue spectrum appearing on the yellow Tes-Tape is indicative of the presence of glucose, since the color development depends upon the oxidation of glucose by its specific enzyme, glucose oxidase.3The advent of Tes-Tape has enabled development of a rapid and simple means for approximating the blood glucose level.