The laboratory medicine is a medical specialty, domain of study and for research, with relevant investigations of patients, with routinally aplications for a proper diseases diagnostic. This activity reviews the ordering and evaluation of laboratory tests and highlights the interprofessional team's role in evaluating and treating patients with the help of laboratory tests. The results of laboratory work are part of the paraclinical investigations that helps establish the diagnosis. Hope this text will be useful for all interested persons, including students.