There are three types of ketone, which are collectively known as ketone bodies, or ketones. In this article, we explain when to check for ketones, the types of tests available, and how to understand the results.
Contents of this article:
What are ketones?
Ketones are produced when the body is forced to break down fats instead of carbohydrates for energy.
The body uses a range of nutrients for energy, including carbohydrates, fats, and proteins. It will use carbohydrates first, but if none are available, the body will burn fat for energy. When this happens, ketones are produced.
Ketones have gained attention in recent years due to the popularity of ketogenic diets, in which people eat a low carbohydrate diet so that their body will burn fat instead of carbohydrates.
There is currently a lack of clear evidence on the benefits of this diet, and there may be some risks, such as high acidity in the blood and loss of muscle.
Typically, carbohydrates are broken down into different nutrients, including blood sugar (glucose), by an enzyme called amylase that occurs naturally in the body. Insulin then transports the sugar to cells to be used for energy.
When sugar can't be used by the cells for energy, the body will start to break down fats for energy instead.
Types of ketone and DKA
Three types of ketones are always present in the blood:
- acetoacetate (AcAc)
- 3-β-hydroxybutyrate (3HB)
The levels of each of these ketone bodies will vary, but they are usually regulated in the blood naturally. For those without diabetes, this is the standard response to starvation.
For those with diabetes, ketone levels can build up and lead to a serious condition known as diabetic ketoacidosis (DKA). This is when ketone levels build up, making a person's blood pH too low or acidic.
DKA can cause someone to lose consciousness, which is known as a diabetic coma and is a medical emergency.
People with type 1 diabetes are at highest risk of developing DKA, but people with type 2 diabetes can develop it as well. Testing ketone levels is an essential part of diabetes care, and checking ketone levels in the blood can help a person to manage the condition and prevent DKA.
Testing ketone levels
Possible symptoms of high ketone levels include persistent nausea, abdominal pain, and fatigue.
A doctor will usually advise individuals as to when, and how often, they should test for ketones. If a person experiences any of the following signs, they may have high ketone levels and should check them:
- blood glucose, or blood sugar, is more than 300 mg/dl
- feeling thirsty often, or having a very dry mouth
- feeling nauseated, vomiting, or experiencing abdominal pain
- persistent tiredness
- confusion, or difficulty thinking as quickly as usual
- a fruity smell on the breath
If a person has only recently been diagnosed with diabetes, many doctors will advise testing twice daily to make sure they are receiving the correct amount of insulin.
Ketone tests measure the level of ketones in either the blood or urine. Older research suggested that urine testing might not always be reliable. However, blood testing has advanced in recent years, and, some blood glucose meters can now test ketone levels.
Urine testing kits
However, urine testing is much more common in the United States. The test is simple to do, and at-home testing kits are available from drugstores or online.
A urine testing kit will include a set of strips, sometimes foil wrapped. To use the test, a person should check that the test is not out of date and follow the instructions on the packaging.
Urine testing kits will usually include a color-coded strip that, after being dipped into the urine, will change color to indicate high levels of ketone, glucose, or protein.
Blood testing meters
Some blood glucose meters can also test ketone levels. To do a blood test using a blood glucose meter, a person should:
- put a blood ketone strip into the blood glucose meter
- prick finger using the needle provided
- press finger to strip to transfer a small drop of blood
- wait for the result to show on the meter
Understanding the results
Ensuring that food is available at regular intervals, especially when travelling, may help to prevent blood sugar levels falling.
The amount of ketone in the blood can be either low/normal, medium/moderate, or high/large. Having medium or high levels of ketones in the blood is sometimes referred to as ketonemia and is a sign that a person's diabetes may not be under control. High levels of ketones is also a risk factor for DKA.
If a person's results are persistently moderate or high, their medication may need to be adjusted, or they may need to make some lifestyle changes.
There are three key reasons why a person would have moderate or high levels of ketones in their blood:
- Lack of insulin in the blood: Someone with diabetes may need to adjust the amount of insulin they take.
- Low blood sugar: Also known as hypoglycemia, this most often occurs in the morning when insulin levels drop.
- Not having eaten enough food: It is essential for someone with diabetes to eat regularly, so as not to let blood sugar levels drop.
If a person's ketone levels are moderate after more than one test, or if ketone levels are high, they should consult a doctor promptly. If they have high ketone levels alongside any symptoms of DKA, they should seek urgent medical attention.
Ketone is produced by the body when there is not enough insulin in the blood. Although the body usually manages these levels naturally, it is often not possible for someone with diabetes.
Regular testing is easy to do at home and should be a standard part of managing diabetes. Trying to keep blood sugar at a healthy level and being aware of the symptoms and risk factors of DKA should help to keep ketone levels within an acceptable range.