Home › Biomarkers › Urine ketones
Ketones form when your body breaks down fat for energy because your cells are not getting enough glucose. A small amount of ketones in your urine is normal, but a high level can point to blood that is too acidic.[1]
On this page, you can read what urine ketones are, what the guidelines say about a level that is too low or too high, what affects your level and which other values are best to look at alongside it.
Also known as: ketones in urine, ketone bodies, ketone test. At the lab: USTX.
Normally, your cells use glucose from your blood for energy. Your body gets that glucose from what you eat. If your cells do not get enough glucose, your body breaks down fat for energy instead.[1]
This produces an acid: ketones. They can build up in your blood and in your urine. The test measures how many ketones are in your urine.[1]
Your result may be a number, or a description such as a small, moderate or large amount of ketones.[1]
A lot of ketones in your urine can be a sign that your blood is too acidic. This often develops quickly and can be life-threatening.[1]
Especially for people with a condition affecting blood sugar regulation, the test helps find high levels early, so they can get care straight away.[1]
Early signs of blood that is too acidic are passing urine often, intense hunger or thirst, dehydration and headaches. Serious signs are nausea or vomiting, stomach pain, confusion, difficulty breathing, feeling very tired or drowsy, and fruity-smelling breath. If you have serious signs, get medical help straight away.[1]
The lab (Labplusarts) gives no numerical limit for ketones in urine: it is a qualitative test. The lab calls a value within the limits normal.[2]
| Value | What it can mean | Who it is for |
|---|---|---|
| A small amount of ketones[1] | Normal | Everyone |
| Small, moderate or large amount[1] | This is how your result may be shown; what is normal depends on what you eat, how active you are and other factors | Everyone; talk to your doctor about what is normal for you |
| High level[1] | Can point to blood that is too acidic | Everyone, especially people with a condition affecting blood sugar regulation |
Source: MedlinePlus (U.S. National Library of Medicine), an explanation of the urine ketone test for the general public.[1]
A high level can point to blood that is too acidic. Because high ketones can cause serious health problems, talk to your doctor about what is normal for you and what your result means.[1]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
On a keto diet, you mainly eat foods with few or no carbohydrates. Your body then uses fat for energy instead of glucose, which can raise your ketones. Eating too little over a long period and an eating disorder can also play a part. Sometimes you need to fast before the test; ask your doctor whether that is necessary.[1]
Exercising too hard for a long time can make your body use fat for energy, and that can raise your ketones.[1]
Long-lasting vomiting or diarrhoea, problem drinking and certain conditions of the digestive system make high ketones more likely.[1]
If you are pregnant, you are more likely to have high ketones.[1]
Ketones in urine are included in BioProfile 77, 87, 121 and 150.[3]
The BioProfile editorial team wrote this page on 10 October 2026 from the sources below, which we read on 10 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert has yet to check this page; after that check, the expert's name and the date of the check will appear at the top. This page offers explanation, not a diagnosis. Discuss a value outside the range with your GP.
