Beta-Hydroxybutyrate, Serum by Liquid Chromatography–Tandem Mass Spectrometry is considered an important tool for evaluating ketone levels in the blood. This analysis is particularly used in the diagnosis and monitoring of medical conditions associated with elevated ketone levels, such as diabetic ketoacidosis or metabolic disorders. The advanced liquid chromatography–tandem mass spectrometry technique allows precise and efficient identification of ketones, helping physicians make treatment decisions based on accurate data. The results of this analysis are also useful in assessing an individual’s nutritional status, especially in ketogenic diets.