Ketones in Urine: When and Why to Test for Them and What They Mean

Introduction

Urine formation is a complex process that involves the filtration of blood in the kidneys followed by the reabsorption of useful substances, and finally the excretion of waste products. One of the waste products that can be found in urine is ketones, which are produced when the body burns fat for energy. In most healthy people who are eating regularly, ketones are usually undetectable or present only in trace amounts in urine. Small amounts can appear normally during fasting, prolonged exercise, a low-carbohydrate diet, or pregnancy. Higher or persistent ketone levels, however, can be a sign of an underlying medical condition.  Ketone testing in urine can therefore provide valuable information about how the body is using energy and may help evaluate certain medical conditions. Let us know more about this in the further sections.

Reasons for Testing Ketones in Urine

A urine ketone test can help detect and monitor conditions in which the body produces excess ketones. When ketone levels rise together with a build-up of acid in the blood, this is called ketoacidosis, a serious condition most often linked to uncontrolled diabetes (diabetic ketoacidosis) or heavy alcohol use combined with poor food intake (alcoholic ketoacidosis). The test may be recommended when ketoacidosis is suspected or to monitor people at risk of developing it^1,2. 

The risk factors for this condition include the following: 

• Uncontrolled diabetes
• Alcohol abuse 
• Vomiting
• Diarrhoea 
• Starvation
• Eating disorders
• Pregnancy 

Note: Some of these factors, such as pregnancy, prolonged fasting, or a low-carbohydrate diet, are more likely to cause mild, harmless ketosis rather than dangerous ketoacidosis, while uncontrolled diabetes and heavy alcohol use carry the highest risk of true ketoacidosis.

Your doctor may recommend you this test if you have the following symptoms:

• Abdominal pain
• Trouble breathing 
• Confusion
• Feeling sleepy or tired
• Unusual fruity-smelling breath
• Excessive thirst or urination

Timing of Ketone Testing

Urbain et al. conducted a study⁸ in 2016 to find out the best time of the day to test for urinary ketones. The results of this study showed that ketones can be reliably detected in the urine in the early morning and after dinner. If you plan to do a ketone urine test at home, it is best to consult your doctor about reliable kits and the most suitable timing for the test.

Methods of Ketone Testing

If your healthcare professional recommends you ketone testing, you would have to provide your urine sample to the laboratory for testing. Your healthcare professional will provide you with cleansing wipes, a container for sample collection and will instruct you about the method for a “clean catch” urine sample².

The following steps should be kept in mind while urine sample collection:

• Wash your hands thoroughly with soap and water and dry them using a towel.
• Next, open the container without touching the inside part of the container.
• With cleansing wipes, you should clean your genital area properly.
• For a few seconds, urinate into the toilet and then stop the flow for a few seconds. During this interval, place the container and start urinating into the container to collect the sample.
• The sample should be collected as per the markings on the container or as instructed.
• Once done, close the container and return it in a polythene bag or as instructed.

Note: If you have menstrual periods or are having piles/haemorrhoids that bleed, inform your healthcare professional before giving a sample. 

Ketone urine test is also known as ketone test, ketone body test or urine ketone test.

Ketone kits are available without a prescription at local pharmacy stores. If you plan to do a ketone test yourself at home, they are usable as it is. However, it is best to always consult the doctors for the most reliable information related to your condition. 

It is worth noting that urine ketone strips mainly detect a ketone body called acetoacetate (and sometimes acetone), but not beta-hydroxybutyrate, which is actually the main ketone produced in diabetic ketoacidosis. Because of this, blood ketone (beta-hydroxybutyrate) meters are often considered more reliable for detecting and monitoring diabetic ketoacidosis, especially during treatment, and your doctor may recommend blood testing in certain situations. 

Did you know ketones are produced by the liver? If there has been a long gap since your last meal, your liver starts breaking down fats, converting them into ketones. Excessive ketone production may lead to ketosis, and in certain situations, particularly uncontrolled diabetes, it can progress to ketoacidosis, a serious medical condition. 

Dr. Siddharth Gupta, B.A.M.S, M.D (Ayu)

Interpreting Ketone Test Results

The normal range for ketones in urine may vary for different laboratories. However, the general qualitative interpretation of urine dipstick results is as follows: 

• Normal: Trace or negative 
• Mild: 1+
• Moderate: 2+
• Severe: 3+

Urine dipstick results are usually reported qualitatively, ranging from negative (not detected) to 4+ (large amount), rather than as a precise number. If a quantitative blood ketone (beta-hydroxybutyrate) test is done instead, a level below 0.6 mmol/L is generally considered normal, with higher levels indicating ketosis, and levels above 3.0 mmol/L especially alongside symptoms raising concern for ketoacidosis^4,5. 

Ketoacidosis can be considered the first sign of type 1 diabetes in people who have not yet been diagnosed. However, those who suspect ketoacidosis should consult a doctor and discuss their symptoms before self-medicating as diabetes is a serious condition.

Dr. Rajeev Singh, BAMS

Significance of Ketone Testing

• Ketone testing becomes important, especially for poorly controlled diabetes, which is the most common cause of ketones in the urine. A study⁷ conducted by Praveen et al. conducted a review in 2021 stated that nearly one-third of Indian children and adolescents with Type I diabetes present with increased levels of ketones. 
• Urine ketone testing may help identify people with diabetes who are at risk of diabetic ketoacidosis (DKA) and indicate the need for prompt medical evaluation. It should not be used on its own to determine insulin dose adjustments unless specifically advised by a healthcare provider. In uncontrolled diabetes, the body starts using fat as a source of energy instead of glucose, producing ketones. This usually occurs because there is insufficient insulin, resulting in high blood glucose levels and an increased risk of diabetic ketoacidosis. 
• The absence or presence of ketones in urine may also help in evaluating fasting hypoglycemia (low blood glucose levels) in childhood and infancy. During fasting, your body uses fat to produce ketones, which serve as an alternative energy source. Thus, an inadequate ketone response during fasting may suggest certain metabolic or endocrine disorders and contribute to hypoglycaemia. 
• The presence of ketones in urine may also occur with excessive alcohol consumption. Alcohol can impair glucose production by the liver, leading to an increase in ketone levels to meet the energy requirements.

Note: The widespread use of blood glucose and blood ketone monitoring has reduced the importance of urine ketone testing for diagnosing and monitoring diabetic ketoacidosis because urine ketones may not accurately reflect current ketone levels.

Also Read: Crystals in Urine: Types, Causes, Symptoms & When to Worry

Conclusion

Testing ketones in the urine is important in people at risk of excessive ketone production, particularly those with poorly controlled diabetes. The ketone urine test may help detect elevated ketone levels and identify people who may require further evaluation for ketoacidosis. The test requires screening urine samples in laboratories for the presence of ketones; these days, urine ketone testing can be conveniently carried out at home too. It is important for individuals, especially those with diabetes, to be aware of their urinary ketone levels and to work with their healthcare providers to maintain a healthy lifestyle and prevent progression or deterioration of their health conditions. 

Frequently Asked Questions (FAQs)

References

1. Ghimire P, Dhamoon AS. Ketoacidosis. InStatPearls [Internet] 2022 Aug 8. StatPearls Publishing. Available at: https://www.ncbi.nlm.nih.gov/books/NBK534848/
2. Ketones in urine. Medline Plus.  National Library of Medicine; 2023. Available at: https://medlineplus.gov/lab-tests/ketones-in-urine/
3. Urbain P, Bertz H. Monitoring for compliance with a ketogenic diet: what is the best time of day to test for urinary ketosis? Nutrition & metabolism. 2016 Dec; 13(1):1-6. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5097355/
4. Dhillon KK, Gupta S. Biochemistry, ketogenesis. InStatPearls [Internet] 2022 Feb 10. StatPearls Publishing. Available at: https://www.ncbi.nlm.nih.gov/books/NBK493179/
5. Baris KU, Sever M, Aksay E, Dogan T, Yalcin N, Eren ES, Ustuner F. Comparing finger-stick β-hydroxybutyrate with dipstick urine tests in the detection of ketone bodies. Turkish Journal of Emergency Medicine. 2014 Jun 1; 14(2):47-52. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4909883/
6. Comstock JP, Garber AJ. Ketonuria. InStatPearls [Internet] 1990. Available at: https://www.ncbi.nlm.nih.gov/books/NBK247/
7. Praveen PA, Hockett CW, Ong TC, Amutha A, Isom SP, Jensen ET, Mohan V, Dabelea DA, D’Agostino Jr RB, Hamman RF, Mayer‐Davis EJ. Diabetic ketoacidosis at diagnosis among youth with type 1 and type 2 diabetes: results from SEARCH (United States) and YDR (India) registries. Pediatric diabetes. 2021 Feb; 22(1):40-6. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7748377/
8. Urbain P, Bertz H. Monitoring for compliance with a ketogenic diet: what is the best time of day to test for urinary ketosis? Nutr Metab (Lond). 2016 Nov 4;13:77. doi: 10.1186/s12986-016-0136-4. PMID: 27822291; PMCID: PMC5097355. Available from: https://pubmed.ncbi.nlm.nih.gov/27822291/

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