It is widely accepted that laboratory tests are commonly used in clinical decision-making and, consequently, play a significant role in patient care. This powerful influence of laboratory tests on clinical decisions puts great pressure on medical laboratories, leading to overuse of tests and violations of evidence-based practices. For medical laboratory services to be conducted in accordance with the law, four fundamental conditions must be met. Firstly, it must be carried out by legally authorized individuals. Secondly, it should align with legally stipulated purposes. Thirdly, it should adhere to the principles and rules recognized by the medical science. Lastly, informed consent from the patient must be obtained. This article examines these conditions that must be followed to ensure the lawful continuation of medical laboratory services.