Modifying Laboratory-Quoted Normal TSH, FT4 and FT3 Reference Range Dependent upon Baseline Characteristics

Introduction: Evidences indicate that the laboratory-quoted normal thyroid hormones as well as TSH reference range could not be always appropriate for everyone in clinical practice. In neonates, infants, children, adolescents and elderly serum concentrations of the thyroid hormones show a clear age and sex dependency. Age- and sex-specific normal reference intervals are an important prerequisite for interpreting thyroid hormone measurement. This study aims to precisely categorize this reference ranges from various updated datasets of serum thyrotropin (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) concentrations in normal people. Materials & Methods: Relevant data were collected by using the Uptodate, PubMed, NCBI, Science Direct with the key words ‘thyroid hormone reference intervals, age; sex; and related TSH intervals’. We included studies describing the variables that changing the thyroid hormone range and excluded references about pathological conditions. We extracted thyroid hormones data in various physiological conditions e.g. pregnancy, menopause etc. This data was inserted in a MS Excel file and subsequently implemented into MATLAB® software as a matrix. A GUI was then developed to calculate individualized thyroid hormone set points based on patient baseline characteristics.Results: From 42 reviewed articles, people categorized into 16 aged group discriminating male and female. For each subgroup upper, lower bound and preferred thyroid hormone concentration were assessed and compared. In comparison to usual laboratory reference range more accurate reference range could be straightforwardly obtained from our developed GUI.Conclusion: The proposed GUI could provide intra-individual physiological optimal ranges compared to laboratory-quoted normal ranges and assist physicians making proper decisions.