Table of Contents
- Key Takeaways
- What Are Ketones
- Recognizing DKA: Warning Signs That Need Emergency Care
- What’s The Difference Between Nutritional Ketosis And Diabetic Ketoacidosis?
- When Should You Test For Ketones?
- How To Test For Ketones: Urine Strips vs Blood Ketone Meters
- What Do The Numbers Mean
- Bottom Line
- References
- FAQs
Key Takeaways
Test for ketones if your blood glucose is above 200 mg/dL, if you’re unwell, or you have symptoms suggestive of DKA, even if your blood sugar is normal and you’re on a SGLT2 inhibitor.
Blood ketone meters are more accurate and measure ketones in ‘real-time’, while urine ketone test strips are cheaper but less accurate.
Nutritional ketosis from a low-carb diet isn’t the same as diabetic ketoacidosis which is a medical emergency most commonly seen in people with type 1 diabetes.
If you have diabetes it’s very likely you’ve heard about ketones, especially if you have Type 1 diabetes where ketone testing is an important part of your management plan. With more people being interested in ketogenic diets, it might also get confusing when you see terms like being ‘in ketosis’ from a low-carb diet vs ‘ketoacidosis’ which is a serious complication of diabetes. They might sound similar but they’re very different things. Read on if you’d like to learn more about the difference between nutritional ketosis and diabetic ketoacidosis, what ketones are, and when and how to test for them.
What Are Ketones
Ketones are chemicals produced by the liver through a metabolic process called ketogenesis, where the body breaks down fat for energy.1 When your cells can’t use glucose for energy, they can redirect to breaking down fats instead as an alternative fuel source. This can happen for several reasons including if there’s not enough glucose (as seen with very low carbohydrate intake) or not enough insulin to move the glucose into cells to use it (seen in type 1 diabetes).
These chemical byproducts are called ketone bodies, and there are two main types called β-hydroxybutyrate and acetoacetate which are acids.2 A third minor ketone body, acetone, is mostly breathed out and can sometimes cause the breath to smell ‘fruity’ when acetone levels are very high.
Recognizing DKA: Warning Signs That Need Emergency Care
It’s normal to have small amounts of ketones. They're important as a backup fuel source for tissues like the brain, especially when there’s not a lot of glucose available during times of fasting, exercise, or limited carbohydrate intake. The problem comes in when the ketone levels become too high, especially in type 1 diabetes where the absence of insulin means the body can’t regulate ketone production.
Diabetic ketoacidosis (DKA) can develop when the ketones build up to the point where they make the blood acidic.3 This can disturb normal bodily functions and become life-threatening if untreated. DKA is more commonly seen in type 1 diabetes, but it can also occur in type 2. It can happen to anyone with type 1 diabetes but it’s more likely if you have not yet been diagnosed, have missed an insulin dose, or aren’t taking enough insulin. You’re also at higher risk in times of increased stress, infection, or illness, so it’s an important condition to be aware of.
The classic symptoms of DKA include4:
Nausea and vomiting
Abdominal pain
Rapid breathing
Confusion or drowsiness
Extreme fatigue or weakness
Fruity-smelling breath
Excessive thirst, dry mouth and frequent urination
Skin flushing
DKA is a medical emergency, so if you have any of the above symptoms or suspect you have DKA, get medical help immediately.
What’s The Difference Between Nutritional Ketosis And Diabetic Ketoacidosis?
A really important distinction that needs to be made in the context of diabetes recently is the difference between nutritional ketosis and diabetic ketoacidosis.
Nutritional ketosis is a normal metabolic response to a very low-carb diet, also called a ketogenic diet. All of us usually burn some fat for energy, which is why we have low levels of ketones. If you reduce the amount of carbs in your diet to levels below 20-50g per day, your body can adapt by increasing the amount of fat it burns to maintain energy production, and this results in higher levels of ketones in the blood, often between 0.5 and 3.0 mmol/L.5 Often this is together with a normal blood sugar level and a normal pH (unlike in diabetic ketoacidosis where blood sugars may be extremely elevated and pH tends to be acidic). It tends to be more of a controlled process, and the difference is that there is some insulin still present to regulate ketone production in nutritional ketosis to prevent it from getting out of hand.
If you have diabetes, make sure to speak with your doctor before starting a ketogenic diet.
Diabetic ketoacidosis can happen to people with diabetes (most commonly type 1) where they have not taken enough insulin, so what happens is that there are high levels of glucose in the blood but their body is unable to take up that glucose into their cells for energy. Their metabolism then rapidly breaks down fats instead, producing ketones. Ketone levels are a lot higher in DKA than what’s seen in nutritional ketosis. Blood ketones are usually above 3 mmol/L (often a lot higher), and the blood sugar level is typically (but not always) elevated, with an acidic pH.
When Should You Test For Ketones?
The American Diabetes Association recommends testing for ketones in several situations for people with diabetes1:
When you have symptoms suggestive of DKA as mentioned above.
When your blood glucose level is above 200mg/dL. High blood sugar in combination with ketones is an early warning sign for DKA.
During an acute illness like a cold or flu, even if blood glucose looks normal
Other than these indications, if you have diabetes you may need to do routine monitoring for ketones during pregnancy, and if you’re taking a SGLT2 inhibitor (a type of diabetes medication) and experience any of the above symptoms, it’s important to test for ketones as when taking SGLT2s you can develop something called ‘euglycemic DKA’.6 This means that you might be in DKA even when your blood sugar stays within a normal range.
How To Test For Ketones: Urine Strips vs Blood Ketone Meters
You can check both blood and urine for ketones, but the results you get from these tests may be different. There are also some combined blood glucose and ketone monitors which means you may not need two different devices.
NovaMax Plus Diabetes Monitoring Kit Combo (Meter Kit, 10 Ketone Strips, and 50 Glucose Test Strips)
$ 34.42
$ 41.78
The Nova Max Plus blood glucose & ketone meter kit is quick, simple, and smart. Nova Max has the newest and most advanced technology that is unique to only Nova Max - semiconductor and nanotechnology - no coding, fastest total test… read more
Diabetic ketone strips used as part of a blood ketone meter tend to be more accurate and give you results in ‘real-time’ but they are also more expensive. They measure β-hydroxybutyrate which is the main ketone body in DKA.
NovaMax Plus Ketone Test Strips - Box of 10
$ 19.09
$ 23.16
Nova Max Plus Ketone Test Strips are designed for use with the Nova Max Plus Meter. Nova Max Ketone Test Strips measure ketone levels in blood with a very small sample, just 0.8 microliters. Results are available in only 10… read more
On the other hand, urine ketone test strips for diabetes detect acetoacetate. They’re inexpensive, widely available and easy to use, but the results you see aren’t how your ketone levels are in ‘real-time’ but rather how they looked a few hours ago.
TRUEplus Ketone Urine Test Strips - 50 Bx
$ 3.90
$ 10.80
Trividia Health's TRUEplus Ketone Test Strips for urinalysis can help you monitor your ketone levels by providing fast and accurate results. It's important to avoid the presence of ketones in your urine. If ketones are present, please see a Doctor… read more
What Do The Numbers Mean
Everyone has low levels of ketones in the blood normally, usually less than 0.6 mmol/L, and this varies between people. For blood ketones, commonly used thresholds are7:
0.6 - 1.5 mmol/L: There are more ketones than usual and a slightly increased risk of DKA. Test again in a few hours.
1.6 - 3 mmol/L: This is a high level of ketones with an increased risk of DKA. Contact your healthcare team for advice straight away or head to your nearest emergency room.
3 or above: This may be consistent with DKA. It’s important to treat this as a medical emergency and seek immediate medical help or go to your nearest emergency room.
If you're using urine test strips and you have a result of moderate to large amounts of ketones, it may mean that you have DKA. It’s important to seek immediate medical help.
Bottom Line
Knowing when to test for ketones and what the results mean is an important part of diabetes self-management, especially in type 1 diabetes. If you know what ketosis is and why it happens, it might help you to understand your test results. Keeping a supply of ketone test strips at home and understanding when you’re at risk of DKA might mean the difference between a phone call to your healthcare team and a hospital admission.
References
American Diabetes Association. Five Things To Know About Ketones. https://diabetes.org/blog/five-things-know-about-ketones
Rahimi N, Gupta, S. Stat Pearls. 2025. https://www.ncbi.nlm.nih.gov/books/NBK493179/
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Symptoms & Causes of Diabetes. https://www.niddk.nih.gov/health-information/diabetes/overview/symptoms-causes
American Diabetes Association. Diabetes and DKA (Ketoacidosis). https://diabetes.org/about-diabetes/complications/ketoacidosis-dka/dka-ketoacidosis-ketones
Gershuni VM, Yan SL, Medici V. Nutritional Ketosis for Weight Management and Reversal of Metabolic Syndrome. Curr Nutr Rep. 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6472268/
Dhatariya K. Blood Ketones: Measurement, Interpretation, Limitations, and Utility in the Management of Diabetic Ketoacidosis. Rev Diabet Stud. 2016. https://pmc.ncbi.nlm.nih.gov/articles/PMC5734222/
Evans K. Diabetic ketoacidosis: update on management. Clin Med (Lond). 2019. https://pmc.ncbi.nlm.nih.gov/articles/PMC6771342/
FAQs
Can I test for ketones using a regular blood glucose monitor?
Most standard glucose meters only measure glucose, not ketones. If you’re testing for ketones you’ll need either urine ketone strips or a blood ketone meter with ketone test strips. There are however some meters, like the Nova Max, which can measure both blood glucose and blood ketones using different strips.
Can people with Type 2 diabetes get DKA?
Yes, but it’s more common in type 1 diabetes. The risk is higher during illness, with very poorly controlled blood sugar, and people taking insulin or SGLT2 inhibitors.
Will exercise help if my blood sugar and ketones are high?
Although exercise is often a good way to help lower blood sugar levels, it’s not recommended if your ketones are moderate or high as this can mean that your body doesn’t have enough insulin available. If you then exercise in this state, it may raise stress hormones like cortisol, and even end up increasing both ketones and blood sugar levels, and along with it the risk of DKA.
