Abstract: Laboratory measurements of thyroid hormones arises from the fact that the patients origin of diseases in many cases cannot be distinguished based only on clinical examination alone and it can be diagnosed by the laboratory assessment. Although, Serum Thyroid Stimulating Hormone (TSH) is the single unique hormone which is able to predict the thyroid status but the TSH measurement by itself sometimes can be misguiding and prevent the full understanding of thyroid patient. Laboratory evaluation of thyroid hormones, TSH, thyroxine (T4) are the least thyroid hormones although there are many other thyroid related parameters which can be measured, if their evaluation was recommended by the physician. There are many reports in the medical circle on the possible misdiagnosis and eventual mistreatment if the proper clinical cooperation between the physicians and clinical laboratory is either disrupted or mistrusted. The aim of this review is to emphasize the importance of close correlation between physician and clinical laboratory to prevent any possible medical mistake. The application of proper methods and techniques and specific requirement of age and gender reference intervals in the laboratory for the thyroid hormones measurements is strongly recommended to have the full confidence of the physician and to avoid misdiagnosis and eventual mistreatments of patients involved.