What laboratory test utilizes the diazo reaction?

The diazo reaction is a chemical reaction that is specifically utilized for the detection of bilirubin in urine. This test relies on the ability of bilirubin to react with diazo compounds, resulting in a color change that indicates the presence of bilirubin. The use of the diazo reaction makes it a reliable method for determining bilirubin levels, which can be important in diagnosing conditions related to liver function and hemolysis.

The other tests mentioned do not involve the diazo reaction. For instance, the protein test typically uses the Biuret reaction or other methods to detect protein levels, while the glucose test often involves the oxidation-reduction reactions of glucose oxidase. The ketone test relies on methods such as the nitroprusside reaction, which is distinct from the diazo reaction. Therefore, the correct answer highlights the unique application of the diazo reaction specifically in bilirubin detection.