with more stability at room temperature, less chances of transmission of blood-borne diseases, minimum precautions for storage with minimal or no need of preservatives, and no need of special training for the laboratory personnel to handle saliva sample. [1][2][3] Its use in monitoring endocrine disorders including Cushing's syndrome, adrenal insufficiency, ovarian function disturbances, testicular diseases, hyperthyroidism, etc. 1,3,4 has been studied.Studies on hormone measurement in saliva have shown that the salivary hormone levels reflect the plasma free fraction which is the biologically active form of the hormone. [5][6][7][8] Previous studies have measured the salivary thyroxine levels using radioimmunoassay (RIA) 9,10 and stable Isotope-dilution liquid chromatography/tandem mass spectrometry (LC/ESI-MS/MS). There is little available information on the levels of TSH, thyrotropin in saliva, which is the most reliable test of clinical importance for diagnosing hypo-and hyperthyroidism in the outpatient setting and follow-up of patients with thyroid dysfunction. 11 Similarly, literature with respect to T3 levels in saliva is limited. T3 testing along with freeT4 (FT4) is useful in diagnosing and monitoring hyperthyroidism. 12,13 The sampling time is important for hormonal assays since the secretion of hormones is under the control of trophic hormones secreted by the hypothalamus. 14 The present study was thus taken up to study the thyroid hormones, i.e., total T3 (TT3), total T4 (TT4), TSH, free T3 (FT3), and FT4 in healthy individuals along with diurnal variations.
MATERIALS AND METHODSA total of 30 healthy subjects from among the hospital staff and students of Sri Venkateswara Institute of Medical Sciences, Tirupati without any history and evidence of thyroid disease were included after informed consent. Individuals with oral disorders, history of diabetes mellitus, and smoking, acute illness, those on cholesterollowering drugs, steroids, and pregnant women were excluded from the study. The study was approved by the institutional ethics committee.
Sample Size CalculationThe sample size was calculated based on previous study 10 using Master statistical software version 2.0, a software developed by Christian Medical College, Vellore.