The accumulation in the body of the ketone bodies: acetone, beta-hydroxybutyric acid, and acetoacetic acid (Taber's Medical Dictionary, 18th ed.). This condition results from incomplete metabolism of fatty acids and is common found in poorly controlled diabetes. It may also be caused by starvation, pregnancy, and high fat diets. Excess ketone bodies are excreted in the urine causing a condition known as ketonuria.
In the olden days before glucometers, the amount of ketone bodies found in urine (identified by dipsticking random urine sample) determined the amount of insulin the patient required.