That said, increased ketones can serve as a warning sign for a serious condition. On the other hand, it tells you whether a weight loss and health-promoting diet such as keto is working.
In this article, you’ll learn what ketones are, the reasons to test for their presence, when to do it, and what the results mean.
Ketones are chemicals produced by the liver when carbohydrates are low. When a person’s blood sugar level decreases in the absence of carbs, your brain and body has to obtain another source of energy in order to keep functioning — and ketones serve as that alternative fuel (*).
The ketones acetoacetate (AcAc) and beta-hydroxybutyrate (BHB) are your primary ketones, and they provide energy. Acetone is considered the least abundant ketone. It arises from the decarboxylation of acetoacetate and excreted in your breath (* , *).
You’ll be able to test ketones via your blood, breath, and urine. Later in this article, we’re going to discuss each of these testing methods.
It’s worth noting that healthy individuals continually produce just a small amount of ketones in the background. However, their levels increase when you’re in a starvation mode or intentionally reducing the amount of carbs in your diet (*).
This is why people on the keto diet enter a state of ketosis (increased ketones) after reducing carbs to 50 grams or lower in a matter of days.
Ketone testing is often done in people with type 1 diabetes. Type 1 diabetes is when your pancreas fails to make or produces only little insulin, the hormone that regulates blood sugar by allowing it to enter the cell to be used for energy (*).
It’s important for type 1 diabetes patients to have their ketone levels checked to avoid developing diabetic ketoacidosis or DKA, which is a medical emergency. This is when there isn’t enough insulin and so your liver ramps up fat breakdown, causing ketones to continuously rise. As a result, your blood becomes acidic, thus the term ketoacidosis (*).
Note that while type 1 diabetes patients are more prone to DKA, this can still happen in those with type 2 diabetes — although it’s rare.
Another reason for ketone testing is when you’re following a keto diet. The goal of the keto diet is to enter a state of ketosis by reducing carbs to 50 grams or lower so your body burns fat rather than glucose, for fuel.
While there are signs and symptoms indicating you’re in ketosis, ketone testing provides objective data. That way, you’ll be more certain that the keto diet is working to your advantage.
For those with diabetes, a doctor will usually order ketone testing when you have these signs and symptoms of DKA. Make sure that you’re also paying attention to the following if you’re managing your diabetes at home(*):
- Urinating more frequently
- Fruity or acetone-smelling breath
- Increased thirst
- Tiredness or sleepiness
- Nausea or vomiting
- Blood sugar concentration is more than 13.9 mmol/l or 250 mg/dl
- Stomach pain
You may also be at risk for developing DKA when you’re sick, pregnant, emotionally stressed, have consistently missed your insulin doses, or taken expired or spoiled insulin (*).
On the other hand, keto dieters may test to confirm ketosis by noting keto flu symptoms, such as (*):
- Decreased exercise tolerance
- Trouble sleeping
- Diarrhea or constipation
These keto diet side effects are only temporary and they resolve in a few days or weeks. When they do, you’ll experience positive ketosis signs and symptoms, which include increased energy, decreased hunger, and weight loss.
When you have diabetes, high ketones in your urine, blood, and breath will help you receive immediate medical attention. Contrastingly, this gives insight into your progress on keto and make adjustments as you go.
Urine strips are a convenient and affordable way to determine increased ketone levels. You can purchase them at any local pharmacy or from Perfect Keto. Checking your urine ketones may be done in the early morning or a few hours after dinner time (*).
Here’s how urine testing is done:
- Prepare the materials needed (the test strip and a clean or sterile specimen container).
- Collect fresh urine sample in the container.
- Dip the end of the strip (with the reactive pad) into your urine specimen.
- Wait for about 40 seconds.
- Check and match the color of the reactive pad with the color chart on the bottle container of the strips or the test kit wrapper.
Urine ketone level color charts show a range of colors, from light to dark, with corresponding mmol/L ketone levels:
|URINE KETONE LEVELS|
|No change in color||Negative ketones|
|Light pink||Trace ketones, 0.5 mmol/L|
|Hot pink||Small ketones, 1.5 mmol/L|
|Magenta||Moderate ketones, 4.0 mmol/L|
|Red violet||Large ketones, 8.0 mmol/L|
|Deep violet||Larger ketones, 16 mmol/L|
Blood ketone testing is the most accurate way to measure your ketone levels. It directly checks beta-hydroxybutyrate (BHB), which is the most abundant ketone (*). Research also shows that for diabetes patients, blood testing is more sensitive and specific to DKA, making it a better option than urine testing (*).
In order to test your blood ketone levels, you need a ketone blood meter and blood test strips. The meter is a small plastic device that fits in the palm of your hand and you can find one at most drug stores or you can order the device online.
Here’s how blood testing is done:
- Prepare the test kit.
- Make sure that you wash your hands and dry them. Alternatively, you may cleanse your finger using an alcohol swab.
- Insert a test strip into the ketone meter.
- Prick the side of your finger using the lancing device. (Blood ketone kits usually include a lancing device.)
- Place a drop of blood on the test strip and wait 10 seconds to get the final reading.
Below are common blood ketone readings and what they mean.
|BLOOD KETONE LEVELS FOR DIABETES PATIENTS|
|None to 0.3 mmol/L||No action needed, just resume regular blood sugar monitoring|
|0.3 to 1.5 mmol/L||Check for DKA signs and symptoms and test your blood sugar more frequently|
|1.5 to 3.0 mmol/L||Check for DKA signs and symptoms and call your healthcare provider.|
Some meters check both ketone and blood sugar levels. Take note that high ketones but stable, low blood sugar is a sign that you’re in ketosis. On the contrary, high ketones with high blood sugar levels indicate possible DKA.
|BLOOD KETONE LEVELS FOR KETO DIETERS|
|0.5 to 1.5 mmol/L||Light to moderate ketosis|
|3 to 5 mmol/L||Transient increase due to exercise|
|5 to 10 mmol/L||Due to fasting for several days, not sustainable long-term. This may lead to nutritional deficiencies due to lack of food intake and possibly a loss of lean muscle.|
Breath testing is one of the newest ways to measure your ketone levels. It measures acetone, the least abundant ketone that’s exhaled through your breath.
As a general rule, the more acetone is in your breath, the deeper you are in ketosis. Acetone is also a great indicator of fat loss, making breath testing a useful tool for monitoring fat loss in healthy people (*). Like urine testing, breath testing is convenient and non-invasive (*).
|BREATH KETONE LEVELS|
|4 to 30 ppm||Ketosis resulting from following a keto diet|
|Up to 170 ppm||Due to fasting, but also check for DKA signs and symptoms if you have diabetes. Call your healthcare provider if you’re concerned.|
|Up to 1,250 ppm||Possible DKA. Call your healthcare provider immediately.|
Regardless of your ketone testing method, high ketone levels, high blood sugar levels, and the presence of diabetic ketoacidosis signs and symptoms need medical attention.
Contact your diabetes team right away. They may give you instructions on bringing your ketones down, such as drinking more water or going to the hospital for further evaluation and to receive IV insulin therapy.
Aside from possible DKA, high ketones may be caused by factors, such as:
- Drinking too much alcohol (which isn’t advised on the keto diet)
- Prolonged and intense exercise (*)
- Eating too low protein while also restricting carbs
- You’re feeling ill
Monitoring ketones and blood glucose regularly helps to prevent emergencies in those with health conditions like diabetes.
Find out more answers to common questions on how to test ketone levels:
What is a good ketone level for ketosis?
The optimal level for keto dieters ranges from 0.5-3.0 mmol/L if you’re checking blood ketones or urine ketones. When checking breath ketones, this would translate to 4 to 30 ppm.
How do you know if your ketone levels are high?
In addition to noting your ketone readings, you’ll likely notice signs and symptoms, such as fatigue, fruity smelling breath, nausea, headache, frequent urination, and digestive issues. While these indicate nutritional ketosis, they may also serve as warning signs for impending ketoacidosis — especially when diabetic individuals have high blood glucose readings.
Which ketone testing gives the most accurate result?
Blood ketone meters allow for more accurate measurements because they detect BHB, your predominant ketone. However, if you don’t have a blood ketone meter at home or are personally not comfortable with this method (because it involves pricking), you can opt for urine and breath testing.
When should ketones be tested?
For diabetic individuals, test for ketones anytime if your blood sugar is above 250 mg/dL and you’re not feeling like yourself. For keto dieters, testing can be done early morning or 3 hours after you’ve had lunch or dinner. It would make sense to check your ketones at the same time each day if you wish to monitor them over a period of time.
How can I test my ketones at home?
While a blood ketone meter is the most reliable way to test, urine strips and a breath testing device (called a breathalyzer) are convenient tools that can be used at home. In fact, you can bring these anywhere — at work and during your travels anytime you need quick results.
What time of day are ketones highest?
Ketone levels may be higher in the morning if you’ve fasted overnight. However, it’s important to remember that ketones can also fluctuate throughout the day. Different factors influence ketone readings. This includes the food you’ve eaten and exercise.
Ketone testing is optional for keto dieters but it can be very useful when you’re just starting out. However, it’s a must for those who have diabetes, especially type 1 diabetes, to prevent diabetic ketoacidosis (DKA) and receive timely intervention from their healthcare provider.
Overall, testing and monitoring is a great way to make informed decisions, whether you’re trying to optimize your new low-carb lifestyle or managing your health. Want to check your own ketones at home or anywhere? Grab our ketone test strips today.