A positive result of Benedict's test is indicated by a color change from clear blue to brick-red with a precipitate.

Generally, Benedict's test detects the presence of aldehyde groups, alpha-hydroxy-ketones, and hemiacetals, including those that occur in certain ketoses.

In example, although the ketose fructose is not strictly a reducing sugar, it is an alpha-hydroxy-ketone which results to a positive test because the base component of Benedict converts it into aldoses glucose and mannose.

[2] The common disaccharides lactose and maltose are directly detected by Benedict's reagent because each contains a glucose with a free reducing aldehyde moiety after isomerization.

Glucosuria can be indicative of diabetes mellitus, but Benedict's test is not recommended or used for diagnosis of the aforementioned condition.

As color of the obtained precipitate can be used to infer the quantity of sugar present in the solution, the test is semi-quantitative.