The Diurnal Variation of Thyroid Hormones in Individuals Attending Tertiary Care Hospital, Kanchipuram District

Abstract

Free thyroxin hormones FT4 and FT3 are unbounded thyroid hormone are biologically active and involves in regulation of metabolism. Measuring the concentrations of free thyroid hormones is of great diagnostic value. A cross sectional study was carried out during the March 2019 to September 2019 in patients between 18 years to 60 years. A total of 60 samples were collected from 30 patients attending Karpaga Vinayaga Institute of Medical Sciences at morning (6am-8am) and 2nd sampling at night (8pm-9pm). FT4, FT3 and TSH were measured by Enzyme linked immunosorbent assay, using Avantor kit.In our study 36.67% participants were males, 63.3% participants were females. The mean FT3, FT4 and TSH in day are 2.43±0.56, 1.14±0.44 and 2.74±3.16 respectively. The mean night FT3, FT4 and TSH are 2.66±0.55, 1.3±0.61 and 3.21±3.18 respectively. The one sample t test shows difference of FT3, t 4.489 and p value 0.000, FT4, t value 3.092 and p value 0.004 and TSH t value 3.394 and p value 0.002. The time of blood sampling has an important role in the interpretation of TSH levels. However fluctuations in diurnal variations in thyroid hormone levels are less. In our study although statistically significant, all the values are within the normal biological reference interval Further studies in larger cohorts is essential to desire important conclusions.