In which condition are ketones present in the urine?

Ketonuria is the condition characterized by the presence of ketones in the urine. Ketones are produced when the body metabolizes fat for energy, often due to insufficient carbohydrate availability, such as in cases of diabetes mellitus, prolonged fasting, or low-carbohydrate diets. When ketone levels become elevated in the body, they can spill over into the urine, leading to ketonuria. This condition can be an important indicator of metabolic changes in the body and is often monitored in patients with diabetes to assess their metabolic state and risk for diabetic ketoacidosis.

The other options refer to different conditions pertaining to substances found in urine under various pathological states. Hematuria involves the presence of blood in the urine, indicating possible issues such as urinary tract infections or kidney stones. Hemoglobinuria refers to the presence of free hemoglobin in the urine, usually as a result of hemolysis, while myoglobinuria involves the release of myoglobin into the urine, typically following muscle injury. Each of these conditions highlights different underlying health issues, but only ketonuria specifically relates to the presence of ketones in urine.