Urine Ketones The ketone pad on the multi-reagent dip stick detects mainly acetoacetic acid and acetone; ß-hydroxybutyrate is not detected. The ketones react with sodium nitroprusside which forms a purple color change. Ketonuria indicates deranged energy metabolism such that fat is used in excess of carbohydrate. This can result in production of the ketone bodies in amounts greater than can be metabolized by peripheral tissue; filtration into urine in excess of tubular reabsorption then results in ketonuria. Some specific causes include:
	Unregulated diabetes mellitus Pregnancy toxemia in sheep Bovine ketosis (For more information on pregnancy toxemia and bovine ketosis, refer to the Glucose section in the Clinical Chemistry module.) Starvation or malnutrition, especially in immature animals Because the color change on the dipstick can be quite subtle, positive reactions are confirmed with the Acetest. This comes in tablet form and contains lactulose to enhance the color change. The reaction with the Acetest is much more apparent than on the dipstick pad. The Acetest is useful for semi-quantitatively measuring ketones in other fluids, such as plasma, serum and milk.