MedlinePlus Medical Encyclopedia: Ketones

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Ketones - urine

Contents of this page:
Illustrations Alternative names Definition How the test is performed How to prepare for the test How the test will feel	Why the test is performed Normal Values What abnormal results mean What the risks are Special considerations

Illustrations

Male urinary system

Alternative names Return to top

Ketone bodies - urine; Urine ketones: acetone, acetoacetic acid, and beta-hydroxybutyric acid

Definition Return to top

A ketones urine test measures the presence or absence of ketones in the urine.

How the test is performed Return to top

Child or adult:
Collect a "clean-catch" ("midstream") urine sample. To obtain a clean-catch sample, men or boys should wipe clean the head of the penis. Women or girls need to wash the area between the lips of the vagina with soapy water and rinse well. As you start to urinate, allow a small amount to fall into the toilet bowl (this clears the urethra of contaminants). Then, in a clean container, catch about 1 to 2 ounces of urine and remove the container from the urine stream. Give the container to the health care provider or assistant.

Infant:
Thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on your infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia. Diaper the infant as usual, covering and securing the bag. Check the baby frequently and remove the bag after the infant has urinated into it. Active infants may displace the bag, so it may take more than one attempt to obtain the specimen. Drain the urine into a container and give it to the health care provider.

Urine ketones are usually measured as a "spot test" with a dipstick containing a color-sensitive pad impregnated with specific chemicals which react with ketone bodies. A color change is a qualitative indicator of the presence of ketones.

How to prepare for the test Return to top

A special diet may be recommended, and drugs that may affect the test results should be discontinued (see Special Considerations).

If the collection is being taken from an infant, a couple of extra collection bags may be necessary.

How the test will feel Return to top

The test involves only normal urination, and there is no discomfort.

Why the test is performed Return to top

Ketones (beta-hydroxybutyric acid, acetoacetic acid, and acetone) are the end-product of rapid or excessive fatty acid breakdown. As with glucose, ketones are present in the urine when the blood levels surpass a certain threshold. Fatty acid release from adipose tissue is stimulated by a number of hormones including glucagon, epinephrine, and growth hormone. The levels of these hormones are increased in starvation (whether related to excess alcohol use or not), uncontrolled diabetes mellitus, and a number of other conditions.

Normal Values Return to top

A negative test result is normal. Results of the presence of acetone in the urine are usually listed as small, moderate or large with these corresponding values:

Small - <20 mg/dL

Moderate - 30-40 mg/dL

Large - >80 mg/dL

What abnormal results mean Return to top

A positive test may indicate:

Metabolic abnormalities, including uncontrolled diabetes or glycogen storage disease
Abnormal nutritional conditions, including starvation, fasting, anorexia, high protein or low carbohydrate diets
Protracted vomiting, including hyperemesis gravidarum
Disorders of increased metabolism, including hyperthyroidism, fever, acute or severe illness, burns, pregnancy, lactation or post-surgical condition

What the risks are Return to top

There are no risks.

Special considerations Return to top

Special diets may alter test results. For example, a diet consisting of low amounts of carbohydrates with high amounts of protein and fat may effect the ketone levels.

Drugs that may cause false positive measurements include glucocorticoids.

Update Date: 1/19/2004

Updated by: Irfan A. Agha, M.D., Department of Medicine, St. Louis University, St. Louis, MO. Review provided by VeriMed Healthcare Network.

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