From the Guidelines
The presence of ketones in urine indicates a potential medical emergency, such as diabetic ketoacidosis, particularly in individuals with type 1 diabetes, and requires immediate attention. This condition, called ketonuria, typically occurs when there is insufficient insulin to help cells use glucose or during periods of low carbohydrate intake 1. Ketones are produced when the liver converts fat into fatty acids and ketone bodies. Common causes include uncontrolled diabetes (particularly type 1), starvation, fasting, prolonged vomiting, high-protein/low-carbohydrate diets, or intense exercise.
Key Points to Consider
- In diabetic patients, the presence of ketones alongside high blood glucose levels may signal diabetic ketoacidosis, a serious medical emergency requiring immediate attention 1.
- For diabetics, it's recommended to check urine ketones during illness, when blood glucose is consistently above 240 mg/dL, or when experiencing symptoms like nausea, vomiting, or abdominal pain 1.
- Non-diabetics might notice ketones during fasting or low-carb dieting, which is generally less concerning, but still requires monitoring 1.
- The body produces ketones as an alternative fuel source when glucose is unavailable, but excessive ketone production can disrupt the body's acid-base balance and become dangerous 1.
Recommendations for Ketone Testing
- Individuals who are prone to ketosis (those with type 1 diabetes, history of diabetic ketoacidosis [DKA], or treated with sodium–glucose cotransporter 2 [SGLT2] inhibitors) should measure ketones in urine or blood if they have unexplained hyperglycemia or symptoms of ketosis (abdominal pain, nausea) and implement sick-day rules and/or seek medical advice if urine or blood ketones are increased 1.
- Specific measurement of β-hydroxybutyrate in blood should be used for diagnosis of DKA and may be used for monitoring during treatment of DKA 1.
From the Research
Presence of Ketones in Urine
The presence of ketones in the urine can indicate several conditions, including:
- Diabetic ketoacidosis (DKA), a serious complication of diabetes characterized by high blood sugar levels and the presence of ketones in the blood and urine 2
- Low insulin levels and high levels of counterregulatory hormones, which can lead to the production of ketones by the liver 3
- Fasting or prolonged exercise, which can cause the body to break down fat for energy and produce ketones 3
- Pregnancy or being a neonate, in which ketones are normally present in the blood 3
- Euglycaemic diabetic ketoacidosis, a condition in which the blood sugar levels are normal, but ketones are still present in the urine 4
Detection of Ketones
Ketones can be detected in the urine using a nitroprusside test, which detects acetoacetate (AcAc) in the urine 3. However, this test has some limitations, such as providing only a semiquantitative assessment of ketone levels and being associated with false-positive results. Newer tests that measure 3-beta-hydroxybutyrate (3HB) levels in the blood or urine may provide more accurate and reliable results 3.
Clinical Significance
The presence of ketones in the urine can have significant clinical implications, particularly in patients with diabetes. It is essential to monitor ketone levels and manage them appropriately to prevent complications such as DKA 2. In some cases, the presence of ketones in the urine may require adjustments to insulin therapy or other treatments 5, 6.