Hyperglycemia and Ketone Testing


Hyperglycemia means high blood sugar. For people with type 1 diabetes, hyperglycemia caused by insufficient insulin can lead to diabetic ketoacidosis, a very serious situation that requires emergency medical treatment. Hyperglycemia can also be caused by eating too much food, which requires treatment to lower blood sugar levels but which does not lead to DKA. The only way to determine between the two situations is through ketone testing.

Causes of Hyperglycemia

  • Eating too much food relative to the amount of insulin injected
  • Missing an insulin injection
  • Blockage in insulin pump tubing
  • Disconnected insulin pump infusion set
  • Illness or stress

Symptoms of Hyperglycemia

  • Frequent urination
  • Frequent thirst
  • Blurry vision
  • Dry mouth
  • Fatigue

Testing for Ketones

There are two ways to test for ketones: urine testing and blood testing. Just as blood glucose testing proved to be superior to urine glucose testing, so too is blood ketone testing proving to be better than urine ketone testing. Ketones appear first in the blood, then in the urine after being filtered by the kidneys. Thus the body has been producing ketones for a while before you can detect them in the urine.

Since ketones in the blood can be detected well before ketones in the urine, there is the possibility to treat sooner than you would if you waited for urine testing to show a positive result. Blood ketone testing can be easier for parents who have very young children with diabetes who do not always have the ability to urinate on command. Also, being able to test with a finger stick eliminates the need to find a bathroom to test if you're away from home or when kids are at school.

Two recent studies (February 2006) demonstrate clear medical benefit from blood ketone testing. The first study (Diabetic Medicine 23 (3), 278-284) showed a significant reduction in hospitalizations during sick days (38 vs. 75 per 100 patient days) for people who used blood ketone testing compared with urine ketones testing. Staying out of the hospital is a very powerful argument for using blood ketone testing. The second study (Diabetes Technol Ther. 2006 Feb;8(1):67-75) showed that, for patients using insulin pumps, blood ketone testing could identify interruptions in insulin flow faster and more accurately than even blood glucose monitoring and could thus help pumpers prevent DKA better than if they didn't use blood ketone testing.

Whether you choose blood or urine ketone testing, it's important to keep a fresh stock of test strips on hand at all times. You don't want to find yourself or your child sick and then discover that you have nothing to check ketones.

At this time, however, blood ketone testing is more expensive than urine ketone testing. A Precision Xtra meter costs about $65 in the United States (though it is often on sale at drug stores), and the ketone test strips cost about $30 for eight, or about $3.75 per test. In contrast, urine test strips can cost as little as 16 cents per strip (vial of 100 Ketostix) to as much as 40 cents per strip (package of 20 foil wrapped Ketostix). While sometimes insurance in the US will cover the cost of the blood ketone test strips, they still cost more than urine test strips. Regardless of this additional cost, the clinical benefits described in recent studies still argue for using blood ketone testing.

Blood Ketone Testing

The Precision Xtra blood glucose meter can also be used to test for blood ketones. As of February 2006, this is the only meter than can test for blood ketones. Because of the importance of identifying ketones as soon as possible, everyone with type 1 diabetes might want consider a Precision XTRA for blood ketone testing, regardless of which blood glucose meter they use. For children and teens, particularly at school, testing for blood ketones rather than urine ketones might be more convenient, easier to use, and therefore more like to actually be used.

The following chart can help you interpret the results of the Precision XTRA's blood ketone test results:

Blood Ketone Reading Indications
Above 1.5 mmol/l
Readings above 1.5 mmol/l in the presence of hyperglycemia indicate that you may be at risk for developing diabetic ketoacidosis (DKA). Contact your healthcare provider immediately for advice.
0.6 to 1.5 mmol/l
Readings between 0.6 and 1.5 mmol/l may indicate the development of a problem that may require medical assistance. Follow your healthcare provider's instructions.
Below 0.6 mmol/l
Readings below 0.6 mmol/l are in the normal range.
Source: Precision Xtra documentation
The Precision XTRA meter, which is the only meter that does blood ketone testing

Urine Ketone Testing

Urine ketone testing uses urine ketone strips to determine the presence of ketones in the urine. These strips are made by many companies, and some familiar brands are Clinistix, Ketostix, and Keto-Diastix. To use urine ketone strips, you either collect a urine sample and dip the test strip into the urine, or you urinate on the test strip. You then wait a specific amount of time and look for a color change in the strip. The color will indicate the amount of ketones in the urine.

Urine test strips typically expire 90 days after a vial of test strips is opened. For that reason, if you use urine ketone strips, you may wish to consider getting a box of individually foil wrapped ketone test strips. While foil wrapped ketone strips are more expensive per strip than a vial of ketone strips (about 40 cents per strip versus as little as 16 cents per strip for a vial of 100), you will likely throw away less strips due to expiration dates and could save money in the long run. Most pharmacies carry vials of ketone strips, but may need to order a box of foil wrapped strips.

This graphic shows a close up of the color chart used to determine the amount of ketones in the urine for Ketostix, one brand of urine ketone test strips:

Label from Ketostix strips showing how color indicates ketone levels in urine

When to Test for Ketones

If the blood sugar is > 240 mg/dl (13.3 mmol/l)1, many diabetes teams recommend testing for ketones. This table offers guidelines for action based on the results of the ketones test.

If ketones are:
Blood: 0.6 to 1.5 mmol/l
Urine: negative to small
If ketones are:
Blood: Above 1.5 mmol/l
Urine: moderate to large
  • Drink lots of water
  • Keep drinking until urine is clear of ketones
  • Take extra short-acting insulin as advised by your diabetes team
  • Continue to check blood sugar and ketones
  • Drink lots of water
  • Contact your diabetes team, as this level of ketones indicates a serious health condition
  • Take extra short-acting insulin as advised by your diabetes team
  • Continue to check blood sugar and ketones

For Additional Information

1 The value of 240 mg/dl [13.3 mmol/l] is a frequently used guideline. Your diabetes team might advise you to use a different value.

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Last Updated: Sun Apr 23 13:59:18 2006
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