Nowadays, Laboratories for medical diagnosis play a basic and crucial role in preserving and promoting the level of the health of society, especially diagnosis system and care of diseases. Regarding the development and expansion of medicine and interference of different elements in distinction. The termination and diagnosis of diseases, the physicians' increasing need to access result of medical tests is necessary and tangible. According to the viewpoint of WHO and its experts, it is impossible to conduct epidemiological and hygienic studies with out using the laboratories for medical diagnoses. At present almost all physicians are not able to apply a clear medical plan to treat their patients without the use of Para clinical capacities. Hence, the connection of the chains in clinical examinations and laboratory diagnosis can help both in realizing and discovering the diseases and with the status of research and generating knowledge in medicine.

The product and outcome of the laboratories for medical diagnosis are integral and unavoidable medical measures in therapeutic process and guaranteeing the health of society. Hence, to assure and to trust these results and their application in therapy are unavoidable and necessary. Nevertheless, laboratories for medical diagnosis are not immune to failures and even executive misconducts. The mistakes committed before conducting tests, while assessing parameters after conducting the tests and those due to the appearance of computer and expansion of its roles to upgrade the quality of clinical services are all included in the failures and misconducts which technical managers of laboratories and practitioners face. These mistakes, sometimes, cause legal and criminal liability. The present article deals with the application of the measures and approaches to prevent such mistakes.