Ketone bodies are the general name of acetoacetic acid, β-hydroxybutyric acid and acetone, which are the products of fatty acid decomposition process. When glucose metabolism is impaired, fat catabolism is enhanced, resulting in increased ketone body production. When the rate of extrahepatic tissue utilization is exceeded, ketone bodies in the blood increase, forming ketonemia; excessive ketone bodies are excreted from the urine, forming ketonuria. Currently, in addition to the qualitative detection of urinary ketone bodies, enzymatic methods are also used directly to quantify the ketone body fraction in the blood. Urinary ketone bodies are often determined using the nitrohydrocyanate test, which reacts with the ketone body components acetoacetic acid and acetone in the urine, resulting in the qualitative determination of urinary ketone bodies. Normal urine is negative for urinary ketone bodies. Positive urinary ketone bodies are indicative of poor outcome or important complications in patients with type 2 diabetes or those undergoing treatment.