**2.1 Analyte**

The detection in a biosensor of the required substance is known as an "analyte." Glucose and lactate continue to be the key analytes of interest among those reported in the literature. A viable commercial solution will likely require significant improvements to sensor life and performance with untreated blood samples of varied viscosity and hematocrit. However, many of the sensors would require dilution of samples for clinical applications. The common analytes are glucose, creatinine, lactate, L-phenylalanine, L-alanine, pyruvate, pyruvate, salicylate, and urea [2–4].
