Today, ketosis is the most detrimental metabolic disease for dairy cows because of milk yield reduction, health disturbances, and the therapy costs that result in significant economic losses. Although, ketosis detection has evolved considerable in the last decade, cases of ketosis are underestimated at herd level due to poor diagnosis. This work systematize the knowledge on basic concepts, methods, analyzes, and monitoring strategies into what can be designed monitoring systems. Advantages but also limits are highlighted as well as some questions that need to be answer through research in order to potentially improve these monitoring systems in the future. This work should be especially useful to Veterinary practitioners but also to undergraduate and graduate students in animal sciences.