How to Test Ketone Levels and What They Mean

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How to Test Ketone Levels and What They Mean

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Learning how to test ketone levels helps you determine diabetic ketoacidosis (DKA) in people with diabetes or nutritional ketosis in those who follow a very low-carb keto diet.

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.

What are Ketones?

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.

Who Needs Ketone Testing?

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.

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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.

When Should You Test for Ketones

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 (*):

  • Fatigue
  • Nausea
  • Headache
  • 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.

How to Test Ketone Levels and They Mean

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 Testing

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:

  1. Prepare the materials needed (the test strip and a clean or sterile specimen container).
  2. Collect fresh urine sample in the container.
  3. Dip the end of the strip (with the reactive pad) into your urine specimen.
  4. Wait for about 40 seconds.
  5. 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
Color Result Meaning 
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 Testing

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:

  1. Prepare the test kit.
  2. Make sure that you wash your hands and dry them. Alternatively, you may cleanse your finger using an alcohol swab.
  3. Insert a test strip into the ketone meter.
  4. Prick the side of your finger using the lancing device. (Blood ketone kits usually include a lancing device.)
  5. 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 
Result  Action 
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
Result Meaning
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

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 (*).

Below are common blood ketone readings and what they mean (* , *):

BREATH KETONE LEVELS
Result Meaning
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.

When Should I See My Doctor?

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 (*)
  • Fasting
  • 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.

Frequently Asked Questions

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.

Summary

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.

17 References

Cantrell C et al. Biochemistry, Ketone Metabolism. 2022 April 28

Laffel L. Ketone bodies: a review of physiology, pathophysiology and application of monitoring to diabetes. 1999 November to December

Hall J et al. Lipid Metabolism. 2021

Dhillon K et al. Biochemistry, Ketogenesis. 2022 February 10

Centers for Disease Control and Prevention. What Is Type 1 Diabetes?.

Centers for Disease Control and Prevention. Diabetic Ketoacidosis.

Dhatariya K. Blood Ketones: Measurement, Interpretation, Limitations, and Utility in the Management of Diabetic Ketoacidosis. 2017 February 10

Cleveland Clinic. Diabetes-Related Ketoacidosis (DKA).

Masood W et al. Ketogenic Diet. 2022 June 12

Urbain P et al. Monitoring for compliance with a ketogenic diet: what is the best time of day to test for urinary ketosis?. 2016 November 4

Newman J et al. β-Hydroxybutyrate. 2017 August 21

Dhatariya K. Blood Ketones: Measurement, Interpretation, Limitations, and Utility in the Management of Diabetic Ketoacidosis. 2017 February 10

Anderson J. Measuring breath acetone for monitoring fat loss: Review. 2015 November 2

Qiao Y et al. Breath Ketone Testing: A New Biomarker for Diagnosis and Therapeutic Monitoring of Diabetic Ketosis. 2014 May 11

Anderson J. Measuring breath acetone for monitoring fat loss: Review. 2015 November 2

Anderson J. Measuring Breath Acetone for Monitoring Fat Loss: Review. 2015 December

Evans M et al. Metabolism of ketone bodies during exercise and training: physiological basis for exogenous supplementation. 2016 December 7

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32 thoughts on “How to Test Ketone Levels and What They Mean

  1. This will be my first try of exogenous ketones! Thanks to Louise Hendon and KetoSummit for all they do and for directing me to Perfect Keto. May your new enterprise be amazingly successful and beneficial to all. ROB

  2. is there any research that indicates that taking exogenous ketones actually increases level of ketosis / fat burning or just falsely raises your level (blood testing)

  3. It is in point of fact a great and helpful piece of information. I’m happy that you simply shared this helpful
    info with us. Please keep us informed like this. Thank you for sharing.

  4. Valuable info. Lucky me I found your web site by accident, and I am shocked why this accident didn’t happened earlier! I bookmarked it.

  5. Just wondering about breath measurements. Does taking PerfectKeto not impact the readings on that at all then? Or it should? Thanks.

  6. Can I presume that the BHB in Perfect KETO is an equal amount of the “d” and “l” isomer? If so, are you investigating the production of a d only isomer product? THX!

    P.S. I LOVE your product and find it particularly beneficial before my morning workouts. And your website has been super helpful in elucidating why I want to use YOUR product. Again, thanks!

    1. Hey Christopher, it’s actually about 70D and 30L and L can actually act as a signaling molecule to decrease inflammation and then convert to D after that. Thanks for the awesome review 🙂

  7. When I take exogenous ketones, I see the level go up to a moderate or high level, but later in the day it goes back to small, but still ketosis. Is this okay?

  8. Does your product come in non-caffeinated. I see that you sell your product on amazon prime. Is it the same product?

  9. How long will my blood bob level remain elevated after taking 1 scoop of the vanilla powder? I took 1 scoop before hiking at 2pm, been in nutritional ketosis for only two weeks now, and had a small carb up meal this evening (home made green curry with butternut squash and bittersweet chocolate after). I tested my level at 8:40pm a couple hours after eating and was surprised to get bhb 2.4 and BG 67. I’ve been running between 0.8 to 1.8. Do you think it could still be the exogenous ketones in my blood? Or maybe this is a sign that I am getting fat adapted?
    I guess if I’m low I will take more in the morning to help with the transition back into keto. I LOVE your products. It is so nice having the keto base as a tool during this first few weeks. I will continue to use the pre workout once I am fat adapted and need a boost. And will always use the MCT powder blended in my coffee with a plug in high power milk frothier. Thank you for everything you guys do!

  10. Why is it that my ketone levels drop way down after a work out – I take perfect keto salt “chocolate” before & during my work out I use blood to test & prior to work keton levels are say 3.00mmoL then after my work out wil drop to 0.5mmoL is that normal or I am I missing something??
    TIA
    Love from to all from down under “Melbourne Australia”

  11. Hello,
    I have a Breath Ketone machine but I have asthma so I have an aversion to breathing all the way out. I received a Ketone Meter for Christmas. I have been having a perfect Keto drink for breakfast with my Bulletproof Coffee. Then I have Lunch. Two Free Range Organic Fed Chicken Eggs and 3 pieces (1 serving) of Bacon and a very small Avocado. After a desk job I go to exercise and then immediately go home and check my Ketos. My numbers are all over the place. Then eat 2oz meat and a big green leafy salad with 1 oz of cheese. Every day to track. What am I doing wrong?
    I am DM I and take Novolog 6 units and AMYLIN – 45 units with food and Levemir 16 units at night. I have plateaued at 180. What else can I do to lose an additional 35 to 40 lbs. Labs are great by the way.

    1. Careful with bacon. It is very difficult to find bacon that has not been cured with some sweetener like cane sugar, maple or honey.

      Try half of the avocado and eliminate the cheese* (* for now. Watch Joe Rogan with Dom D’agostino where he says that fat loss was better when taking out the dairy.

      As for the meter. If you can breath all the way out (I know it’s trying sometimes) great. Otherwise, try to breathe the same way everytime using it meter. I have a Ketonix and it regularly shows 4 green flashes during the first week of induction.

      Make sure that your macros line up with a well formed ketogenic or modified atkins diet. (read up on atkins induction rules)

      Make sure you’re eating enough, and skip the cheat days

      Good luck
      and enjoy your new body

  12. I’ve been taking extogenous ketones with a keto diet for over a month, and have not felt or seen any effect. Today I blood tested 2.5 hrs after drinking them & my levels were too low to even register! 2 days ago I tested 40 minutes after drinking them, .4. I drink them fastest; what could be causing me to not get fat adapted or into ketosis!? My macros are excellent, calories around 1200 a day (female, 5’6”, 168 lbs after gaining almost 5 pounds when I switched to a keto diet). Help!

    1. Take a closer look at the food you are eating.
      Something in there has a sugar or starch that is causing you to not get into ketosis.
      Usually this is going to be some kind of corn derivative: maltodextrin, corn syrup solids, high fructose corn syrup, dextrose … etc (48 different names for corn alone)
      Take a closer look at the ingredients in all the things that you are eating.

      For me: I can be in very deep ketosis and lick a candy and be out of ketosis in 20 minutes!

      Make sure you are following a well formulated ketogenic diet like Atkins induction phase.
      NO MORE than 20 carbohydrates per day and no sugars, fruits, starches, potatoes, breads pastas.

      What you drink must also be considered. Wine, alcohol, juices, etc all contain enough sugars and starches to prevent ketosis.

      what are your macros?
      What does your typical day look like, meal, drink wise?

  13. This is all very useful information. I know a lot of people who think they are on a keto diet however they are eating things that have carbohydrates and they don’t even realize it. Sugar = Carbs!!

  14. I just received your test strips and used one. I’ve looked everywhere and can’t find what the levels SHOULD be, or rather what the optimum level is that we should be striving for. My strip said I’m at moderate level. Should I be striving for higher or lower?

  15. I test for ketosis with pee strips. The color is close to the moderate to stronger but the color is very light. Does the depth of color matter or just the shade of the color, more blue than pink . Is it better to be more tworks the strongest ketosis or is moderate detosis just as good for weight loss?

    1. Are you using Perfect Keto’s test strips? If you are, the color doesn’t have to be an exact match; but generally, when you are first starting keto, you want to be on the darker end of the spectrum (closer to the dark purple). This means that a high amount of ketone bodies are registering on the strips.

  16. I’ve been on the Keto diet for two weeks, along with fasting (can only eat from 11-4:00). I use the urine test strips daily and have stayed at the large 8.0 mmol, but the girl helping me says I have to be at the very extreme larger 16.0 mmol in order to be in ketosis. Is this correct? Or have I reached ketosis with the 8.0 mmol? I’m not sure what the numbers mean. I have been at this for a week and a half and can’t get it to the “larger” one on the test strip.

    1. The optimal ketone level is not known since it is likely different for everyone and varies depending on how long you have been keto for and what your goal is. Most importantly, if you are experiencing the benefits of ketosis then you have reached your optimal ketone range @Tiffany

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