The most common form of ketone test is a home urine test. Available without a prescription, urine ketone tests allow people with diabetes to measure their ketones with a sample of urine. People can also test their ketone levels with a blood sample. Some newer glucose meters measure ketones in addition to glucose (blood sugar).

Testing ketones in a blood sample is considered more accurate than urine testing and may be preferred by some patients because of convenience.  The ability to test with a finger prick eliminates the need to find a bathroom for urine testing. Ketones are also detectable in the blood earlier than in the urine. As a result, a patient may test positive for ketones earlier with a blood test than a urine test. The patient would then be able to treat the ketosis earlier.

Another drawback to urine strips is that they can detect only some of the ketones produced by the body. Ketones consist of acetone, acetoacetic acid and beta-hydroxybutyric acid. Only a blood test can detect beta-hydroxybutyric acid. Therefore, a urine test that does not detect any ketones may be inaccurate because it may be missing the presence of beta-hydroxybutyric acid.

Home urine ketone tests also require the user to compare a test strip to a color chart to read results. The use of a color chart introduces a number of potential problems. Patients must be able to see subtle changes in color to use a urine ketone test, which may not be possible for someone who is colorblind or whose vision is impaired by diabetic retinopathy, glaucoma, cataracts or other eye diseases. A glucose meter does not use colors. Patients also risk comparing the test strip to the chart before it has finished changing color. This can result in inaccurate readings.

Although blood tests for ketones have many advantages, they are more expensive than urine tests. Urine testing requires only disposable test strips. Blood testing requires patients to buy a glucose meter that is capable of measuring ketones, and compatible test strips that are more expensive than urine test strips.

Some physicians may prefer their patients to test their blood for ketones with a glucose meter or they may recommend testing blood in addition to using urine tests. Patients should discuss ketone tests with their physician and ask which method is best for them.

Ketone tests may also be performed in a hospital in order to diagnose ketoacidosis. The test may be conducted on a blood sample from a vein (venipuncture) or on a urine sample.