Ketones and Diabetes

For diabetics, ketones are an essential warning signal. How do they work? Read on…

Under normal circumstances your body uses glucose for energy. For your body to use that glucose, insulin must be present and the glucose must be able to get from the blood into the cells.

If something goes wrong with that system, as it does in diabetes, then the glucose does not get used and builds up in your blood. However your body still looks for energy and so turns to a different source for it’s needs and begins to burn fats.

Ketones are a side product of fat breakdown. Now the glucose and ketones build up in your blood, the kidneys attempt to filter them out and this leads to sugar and ketones in the urine (ketonuria).

Ketones are strong acids - beta-hydroxybutyric acid, acetoacetic acid, and acetone if you are interested in the exact types! - that build up in your body and can lead to diabetic ketoacidosis.

Read on or go directly to -
Who needs to test.
Warning signs that suggest testing for ketones.
When are these tests done?
Urine test.
How the test is done.
Normal Values.
What to do if ketones show up in urine.
What can give false positives in urine tests.
What test strips are available?
Acetest Reagent tablet
Blood ketone test.
How does one measure blood ketones?
Normal values of blood tests.
Freestyle Optium Blood Glucose Meter (Previously - MediSense Optium Xceed Blood Glucose Meter)

Who needs to test.

1. Type 1 diabetics are in danger of developing ketones, which can lead to ketoacidosis, requiring hospitalisation. They should always keep a check on their ketone levels.
2. Type 2 diabetics need to be aware of the warning signs (listed below). Though more rare than in type 1 diabetes, type 2 diabetics can also get ketoacidosis.
3. Pregnant women with gestational diabetes.
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Warning signs that suggest testing for ketones.

1. If your BG readings are 13.3 mmol/l (240 mg/dl) or higher for two or more tests in a row.
2. If your blood sugar is going up (at any level) and you are feeling unwell.
3. If you are ill or think you have an infection. If you are sick, ketones can be present even when your sugar is not high.
4. If you have abdominal pain and/or nausea or vomiting -These can be symptoms of ketoacidosis.
5. If you are extremely stressed, physically or emotionally.
6. If you are planning to exercise and your blood glucose is over 13.3 mmol/l (240 mg/dl)
7. If you are pregnant and your blood glucose is over 13.3 mmol/l (240 mg/dl).
8. If your breath smells fruity.

Types of tests.

There are two tests that can be done for ketones.
1. Urine testing
2. Blood testing
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When are these tests done?

1. As an initial screening test when diabetes is suspected - they help determine the extent of the problem.
2. At least twice daily for the first few days after diagnosis until ketone checks stay negative.
3. To identify why diabetes is out of control. This could be due to the following reasons -

a) Incorrect amount of insulin.

Your insulin regime may need changing. For instance if you are on a once a day injection of long acting insulin you should do a morning ketone test to see if your insulin is lasting the full 24 hours. If ketones are present it may mean you need an extra insulin injection in the evening.
Also morning ketones can be a sign of a low blood sugar during the night followed by a rebound to a normal or high level by morning.

You may have forgotten to inject your insulin. This can happen when you are sick and do not feel like eating - you may think that you do not then require insulin - this is totally incorrect. Hyperglycemia (high blood glucose) caused by insufficient insulin can lead to diabetic ketoacidosis, which is a very serious condition.

b) You are so insulin resistant that your body cannot access the glucose that is present.

c) You are suffering from carbohydrate deprivation and thus lack of glucose because -

You are not eating enough food for your energy requirements - you may be going too long between meals and need to add snacks or you may be skipping meals (naughty, naughty!!!).

Then there is the offhand chance that you are anorexic AND diabetic!

You may also be lacking food because you are throwing up, an especial problem in pregnancy, or if you suffer from bulimia.

You may be eating a low carbohydrate, high protein diet with insufficient fats to balance the loss of carbohydrates.

4. To evaluate whether a person is in a coma due to uncontrolled diabetes or whether the coma is from some other, as yet unknown, cause.
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Urine test.

Preparing for test.

You need no special preparation except to abstain from taking any medications that may interfere with the test results.(See further down this page for the list.)

The urine specimen can be collected at any time of day but must be fresh.

Make sure you have a clean container handy for collecting the sample. Disposable plastic or paper cups work well.

If you do not have such a container it is possible to test by passing a stream of urine over the test pad on the dipstick.

For a child who is not yet toilet trained it is possible to press a test strip firmly against the wet nappy (diaper).
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How the test is done.

A urine sample is taken and the ketones are measured using a dipstick. This is a thin strip of plastic with a pad at the one end that is impregnated with specific chemicals. These chemicals react with ketone bodies and change colour, in a range of rather attractive shades of pinky/purple, depending on the amount of ketones present.
The results are then read by comparing the dipstick to a supplied colour chart.
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Normal Values.

Normal = A negative test result. The pad will not change colour.

Positive values are read as:-
Small - less than 20 mg/dL
Moderate - between 30-40 mg/dL
Large - 40 to 80 mg/dL
Very large - 80 to 160mg.dL

Positive ketones are not considered to be a problem if:-

1. Your blood glucose is within range.
2. If you are fasting or you are on a very strict diet, especially one with very low carb and lots of protein and fats.
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What to do if ketones show up in urine.

The above factors should be discussed with your health care provider at the next visit if ketones are present in small amounts.

If moderate to large amounts are present then you need to get hold of said health care provider immediately as this can be serious. Tell whoever answers the phone that the situation is urgent. (between 30-80 mg/dL)

Very large values mean get to the emergency room fast. DO NOT DRIVE YOURSELF. (Above 80 mg/dL)

Self-help measures you can take if your ketone levels are small, while waiting to contact your health care provider, of if unable to contact your health care providers .
1. Drink plenty of water to ‘wash out’ the ketones. At least 1 glass every 30 minutes.
2. Avoid exercise
3. Drink more water.
4. Check your blood glucose every 3-4 hours.
5. Drink more water.
6. If your BG is over 13.3 mmol/l (240 mg/dl) keep testing for ketones.
7. Drink more water.
8. If your BG is over 13.3 mmol/l (240 mg/dl) and ketones are present and you have short acting insulin then consider taking an extra dose. Keep a careful check on your blood glucose in case of hypos.

If in any doubt you will have to wait for the advice of a health care professional and need to find one somewhere, anywhere, - fast.
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What can give false positives in urine tests.

1. Special diets as discussed previously.
2. Dehydration that can cause ketones to concentrate in the urine.
3. Medications, for example:-
Glucocorticoids (steroids) such as Prednisone - a potent medication used to treat many inflammatory conditions including rheumatoid arthritis.
Levodopa (Sinemet or Larodopa) - used for the for the management of Parkinson's disease.
Phenazopyridine (Pyridium, Geridium, Pyridiate, or Urogesic) - used for urinary tract infections.
Valproic acid ( Depakote, Depakon, or Depakene) - used for the treatment of convulsions, migraines and bipolar disorder.
Vitamin C (ascorbic acid), when taken in large amounts.
Inositol - part of the vitamin B-complex.
Metformin - oral diabetic medication.
Methionine - an essential sulphur-bearing amino acid, potentially beneficial in liver detoxification and in neutralising toxins.
Captopril and other free sulfhydryl drugs.

Other factors that may affect test results:-

1. You have not correctly stored the test strips - If you do not close the lid of the container tightly the strips can be affected by light or moisture.
2. Likewise moisture can affect strips if you remove the desiccant (usually found in a small white packet in the bottle).
3. The strips have been affected by heat because they have not been stored in a cool, dry place - NOT the refrigerator!
4. The test strips have passed their expiry date. Urine test strips usually expire 90 days after a vial of test strips is opened. In the US one can buy foil wrapped ketone strips that last for 2-3 years. These are more expensive (they can be more than double the price) but if you are not testing frequently you may actually save money in the long run by not having to throw away expired strips.
I have not been able to find them in the UK and read that they had been discontinued, sometime in 2011-2012. Apparently they were still available for a while on an online auction site but be very careful if buying like that because you seriously don’t want to waste your money on ones which are out of there expiry date or very soon will be.
Do not use strips at any time if the pad is discoloured.
5. When preparing to do the test you have touched the test area of the strip with your hand or put it down on a surface where it can be contaminated.
6. The urine specimen has become contaminated with bacteria, possibly from the container it was collected in.

As you may have gathered these strips are pretty fussy and it can be really irritating to suddenly find your tub of 100 has stopped showing anything 10 strips in. It may well be better to buy them in as small a quantity as you can get but more often. Though that may appear more expensive, in the long run it can work out cheaper than tossing half the strips away.

This advise is especially pertinent to folk who are not diabetic but on a low carb diet of some sort, who use them to test if they are in a ketogenic state. They tend to test less than a diabetic and frequently find their strips have stopped working long before the tub has finished.

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What test strips are available?

Common product names include:


These are made by Bayer Diagnostics. They test only for acetoacetic acid in urine. May give false negative reading if acetone is present.
They must be read exactly 15 seconds after the strip has been dipped. Use a timer or the second hand on a clock, do not rely on counting!

Reagent strips are available in packs of 50 or 100 strips or packs of 20 foil wrapped strips. The foil-wrapped ones they are less likely to go off, they have a much longer expiry period. They are also easier to carry around with you - you can put one or two in your blood glucose meter case when you go out so you will have them with you if you need them.
Don’t forget to carry the colour guide chart as well or you won’t be able to read the result!

They are also available as Keto-Diastix which will test for both glucose and ketones. They are more expensive than the straight ketone test strips and not as accurate as your blood glucose meter. They do not come in a foil wrapped option.

Chemstrip K

Made by Roche Diagnostics.
Used to check for urine ketones. Measures acetoacetic acid and acetone.
They differ from Ketostix in the timing. Chemstrip K must be timed for exactly one minute.
They are also available as Chemstrip uGK which will read for ketones and glucose.

Acon urine reagent strips.

Made by ACON Laboratories, Inc. These strips come in a number of different types depending on what they test for.
Their 2 parameter strips test for glucose and ketones, but they have an 11 parameter one that tests for both those plus Ascorbic Acid, Bilirubin, Specific Gravity, Blood, pH, Protein, Urobilinogen, Nitrite and Leukocytes - wow!
Check out
As of 2005 these claim to be available in over 100 countries - except in the US and Canada. I do not know if they have yet become available there.

DiaScreen 1K

Made by Hypoguard Ltd. these strips measure ketones.
DiaScreen 2GK strips measures both glucose and ketones.


Though these strips may be ‘available’ it does not mean you can always buy them, in the UK at least. It appears that because so many dieters use them, one of the large pharmacy chains has taken it upon themselves to stop selling them.
I had heard about this and wondered if it only applied to non diabetics asking for them but when I did a search myself to see if I could buy any, producing proof of my diabetic state, I was told they no longer stocked them. This was company policy because they believe low carb dieting was an unhealthy way to lose weight. If I was prepared to wait 3 weeks one store offered to see if they could order some.
Head office states that they were not actually forbidding their stores to sell them but they were advising that they were part of a very unhealthy way of eating and that the pharmacists may choose to refuse to sell them to non-diabetics. No reason is given as to why they do not advise their pharmacists to keep supplies for those who could prove their diabetic state.
The irony of this is that in every shop I went into I could buy both books and products for the very diets they were describing as unhealthy!

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Finally we come to a slightly different method of testing urine for ketones. This uses tablets, not strips.

Acetest Reagent tablet

are made by Bayer Diagnostics and come in a 100 tablet pack. They can be used with urine or blood and measure acetoacetic acid and acetone.

The method of using them is as follows:-

1. Place the tablet on a piece of dry white paper. Do NOT touch it with your hands. Shake a tablet from the container into the cap and then onto the paper.
2. Using a medicine dropper draw up some of the fresh urine sample and place 1-2 drops on the tablet.
3. Wait for 30 seconds.
4. Compare the colour of the tablet with the colour chart to read the results.
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Blood ketone test.

If we can test for ketones in urine why would we use a blood test - after all are we not ‘sticking’ ourselves enough to check our blood glucose levels?

Well first you need to understand more about ketone production. There are 2 main ketone bodies produced, acetoacetic acid and beta-hydroxybutyric acid (HBA). Acetoacetic acid can break down to form acetone.

As you will have noticed from the information on urine test strips they measure at worst only acetoacetic acid and at best acetoacetic acid and acetone. These two make up less than a fifth of the ketones produced. No urine test measures HBA.

It is possible to have high levels of HBA in the blood but have a urine test that appears negative.

So what I am saying is that a blood test can detect ketones that the urine test misses, making it more accurate. The accuracy of the urine test is also in question if a person is dehydrated and cannot void urine frequently.

Ketones appear in the blood first, and only in the urine after the kidneys have filtered them out of the blood. Your body will have been producing ketones for a long time before they appear in the urine. The blood ketone value tells you the current ketone level at the time the test is done while the urine ketone measurement may lag hours behind, telling you what your ketone value were, not what they are. Measuring ketones in the blood enables you to detect them 2 - 4 hours earlier than in the urine and also it may take 8 to 24 hours for the ketones to clear from the urine.

Instant blood ketone measurement will allow you to monitor the possible onset and development of ketoacidosis and take measures to stop it. It will also help you to determine whether those measures are working.

For patients using insulin pumps, blood ketone testing can identify interruptions in insulin flow faster and more accurately than blood glucose monitoring.

And if you want to forget all the good technical reasons you can go for the simple one - it is less messy than peeing on a test strip or trying to aim into a small cup!
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How does one measure blood ketones?

Fortunately modern technology has come along with meters that measures ketones in the same way as we measure blood glucose - by a fingerprick test (yip, another one, damn it!).

In the US there is the Precision Xtra Meter made by Abbott Diabetes Care, the same people who make the Freestyle range of blood glucose meters.

This meter tests for both blood glucose and blood beta ketones.
You just have to use different test strips and remember to recalibrate for ketone testing.

You get 4 ketone strips in each box of blood glucose strips used by that meter. It is also possible to purchase separate blood ketone strips. These come as 8 foil wrapped strips to a box and cost around $30.

The procedure for using them

is much the same as for taking ones BG levels.
1. First you use a red control strip to calibrate the meter.
2. The proper test strip is then pushed into the test port.
3. You prick your finger and place a drop of blood on the purple hole on the strip.
4. The meter will display the result in 30 seconds.
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Results are read as:-

Less than 0.6 mmol/L. - Normal

0.6 to 1.5 mmol/L. (moderate) - Contact your healthcare provider, drink plenty of water and keep checking, this can become serious..

Greater than 1.5 mmol/L. (high) - This is serious and you must contact your healthcare provider and stress the urgency of the situation. You are possibly developing ketoacidosis. Give short acting insulin if so advised.

Greater than 3.0 mmol/L. (very high) - Get someone else to take you to the Emergency department of your hospital immediately! Do not drive yourself.

Info for dieters

The above advice is for type 1 diabetics. They have to manage both blood sugar and ketone bodies as they do not produce insulin. The knowledge of blood sugar levels and ketone production is essential to enable them to judge the correct amount of insulin to inject.
However non diabetics eating normal amounts of carbs have normal blood sugars and about 0-0,6 of ketone bodies in their blood, because when ketone bodies in the blood rise too high insulin is excreted to lower the fat burning process. A reading of 1-3 occurs when less carbs are eaten, starving the body of glucose and thus forcing it to use fat as fuel, thus producing more ketones. Over 3 can occur as a result of starvation or an exercise induced state.
For folks on a Very Low Carb Diet (VLCD) or a Low Carb Diet (LCD) using these meters to test if they are in a ketogenic fat burning state, a ketone level somewhere between 1.5 – 3 is said to be an optimal level for maximizing weight loss.

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The same meter as above is in the UK called the Freestyle Optium Blood Glucose Meter (used to be called the MediSense Optium Xceed Blood Glucose Meter), also by Abbott Laboratories.

You can use Freestyle Optium Plus strips (used to be MediSense Optium Plus strips) to test your blood for glucose, and the Freestyle Optium B-Ketone Electrode Test Strips (used to be called MediSense Optium B-Ketone Electrodes and Abbott Optium B-Ketone Electrodes.) to test for ketones in your blood.

In the UK the meter costs around £15, the glucose strips about £25 for a box of 50 and the ketone strips are around £30 for a box of 8.

The strips are available on the NHS. See here for details on the meter and strips -

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(checked and updated April 2013)