Glucose, a basic sugar and important energy source, has a molecular formula of C6H12O6. It comes in two major forms, α-glucose and β-glucose, with both forms characterized by a hexagonal ring structure with five carbons and one oxygen atom as well as a sixth carbon atom hanging outside the ring. The two forms (α and β) differ in the orientation of the hydroxyl group (OH) on the first carbon.

Glucose is usually tested by the Benedict’s test, a solution of Benedict’s reagent is heated with the sample. Indication is in a manner that, in a presence of glucose, solution will agitate from blue (no glucose) to green (left) to yellow (mid left) to brick red (right) in a space of reducing sugars. The other common methodology uses glucose test strips that change color based on the glucose concentration of urine or blood.