Qualitative Analysis of Ketone Bodies in Urine
The three compounds, namely, acetone, acetoacetic acid, and β-hydroxybutyrate, are called ketone bodies. Ketone bodies are water-soluble and energy-yielding substances. The synthesis of ketone bodies is called ketogenesis. The ketogenesis process occurs in the liver particularly during periods of low food intake, carbohydrate-restrictive diets, starvation, or in untreated type 1 diabetes mellitus. Ketone bodies are transported from the liver to the extrahepatic tissues and converted into acetyl-CoA which then enters the citric acid cycle and is utilized for energy production. The liver, however, is unable to metabolize ketone bodies. The tissues which lack mitochondria, i.e., erythrocytes, also cannot utilize ketone bodies. Ketone bodies are major fuel source for the brain during starvation and can meet 50–70% of total energy needs. The relative proportion of ketone bodies present in blood may vary from 78% (β-hydroxybutyric acid) to 20% (acetoacetic acid) and 2% (acetone).