Ketosis is a metabolic process that occurs when the body switches from glucose to predominantly fat metabolism for energy production, this happens when carbohydrate availability reaches low levels. The metabolism of fatty acids in the liver results in the production of chemical by-products known as ketone bodies or ketones. Ketosis occurs when the body produces more ketones than the liver can process.

DKA is a serious complication of both Type I Diabetes Mellitus (T1DM), however can also affect individuals with T2DM. The condition is linked to insulin deficiency and occurs when glucose levels are consistently high and insulin levels are severely low. Due to this imbalance glucose builds up in the blood and the body responds by metabolising fat rather than glucose. DKA is usually one of the first indicators of T1DM.

Ketosis is not normally dangerous and is typical of ketogenic diets which are low in carbohydrates. Ketones however are poisonous when present in high levels leading to ketoacidosis, DKA for example if left untreated can cause damage to vital organs and in some instances may lead to a coma or death. DKA is commonly triggered by an illness, infection or missing insulin treatments.

The American Diabetes Association recommends testing for ketosis in diabetics when symptoms of ketoacidosis are present, when
glucose levels are consistently elevated, during pregnancy and if experiencing any illness. NICE also recommend monitoring ketones in patients with T1DM especially during periods of illness.

Semi-quantitative, nitroprusside-based methods remain common for the detection of ketones in the blood and urine of diabetic patients. The nitroprusside method is available in both tablet and reagent test strip form where urine or blood is applied, and a colour change observed. There are several limitations associated with Nitroprusside methods;

1. Capable of detecting only acetone and acetoacetate, as such they lack sensitivity especially in early stages of DKA.
2. The intensity of the colour change observed is subjective compared to quantitative methods like D-3-Hydroxybutyrate which can be used to monitor  recovery and improvements to treatment.
3. Several medications including Valproic Acid and Vitamin C can interfere with nitroprusside methods leading to false positive
   results.
4. False negative results are common as the method does not detect the main ketone body – D-3-Hydroxybutyrate. As ketoacidosis improves and D-3-Hydroxybutyrate is converted to acetoacetate the result with urine dipsticks can appear positive despite the patient’s status improving by this stage.
5. D-3-Hydroxybutyrate is a more reliable indicator of ketosis and DKA due to its superior stability when compared to acetone and
   acetoacetate.

When the carbohydrate stores are significantly decreased, or the fatty acid concentration is increased, there is an upregulation of the ketogenic pathway and consequently, an increased production of ketone bodies. This is commonly observed in alcoholism, type I diabetes and starvation. Most organs, including the brain, can utilise ketones as its source of energy. The liver however, cannot utilise ketones, despite producing them, as the liver lacks the necessary enzyme ketoacyl-CoA transferase ¹.

Ketosis is the presence of ketones. Whilst ketosis is not dangerous, if left untreated, especially in diabetes, ketoacidosis (high levels of ketones) develops ².

In type 1 diabetes mellitus (T1DM), the body is unable to produce insulin resulting in bodily cells not receiving energy from glucose, causing the body to release hormones to breakdown fat for energy, producing ketones. If left untreated, diabetic ketoacidosis develops, a serious health condition. Diabetic ketoacidosis is commonly triggered by an illness, infection or missing insulin treatments ³.

There are three main ketones produced as a result of ketosis; D – 3 – Hydroxybutyrate, acetoacetate and acetone.

D-3-Hydroxybutyrate is the most abundant of the three accounting for 75% of total ketones in the body, it is later catabolised into acetoacetate and then into acetone. Due to the higher levels of D-3-Hydroxybutyrate, it is the more sensitive marker for the diagnosis of ketosis, in particular DKA.