Ketones in urine (ketonuria) and Ketones in urine test


Ketones are organic compounds that contain a carbonyl group (C=O) attached to two carbon-containing groups. Ketones are produced by the breakdown of fatty acids in the liver and can be used as an alternative source of energy by most cells in the body when glucose is scarce or unavailable.

Ketone bodies are three types of ketones that are formed in the liver during a metabolic process called ketogenesis. The three ketone bodies are acetoacetate, beta-hydroxybutyrate, and acetone. Acetoacetate and beta-hydroxybutyrate are acidic molecules that can lower the blood pH if they accumulate in excess. Acetone is a volatile and reactive molecule that can be exhaled through the lungs, giving a fruity odor to the breath.

Ketogenesis occurs mainly in the mitochondria of liver cells when there is a lack of carbohydrates or an excess of fatty acids in the diet. The liver converts fatty acids into acetyl-CoA, which then enters the ketogenesis pathway to produce acetoacetate. Acetoacetate can be reduced to beta-hydroxybutyrate or decarboxylated to acetone. The liver releases these ketone bodies into the bloodstream, where they can travel to other organs and tissues that can use them for energy production.

Ketone bodies play an important role in providing energy for the brain and heart during periods of fasting, starvation, or low-carbohydrate diets. The brain normally prefers glucose as its main fuel source, but it can adapt to use ketone bodies after several days of carbohydrate restriction. The heart also uses ketone bodies as a preferred fuel source over glucose or fatty acids. However, excessive production of ketone bodies can lead to a dangerous condition called ketoacidosis, which occurs when the blood becomes too acidic and affects the normal functioning of various organs and systems. Ketoacidosis can be caused by uncontrolled diabetes, alcoholism, or prolonged starvation.