Establishment of Reference Intervals to Value of Thyroid Function Tests in Cord Blood of Neonates Born in Two Hospitals, Addis Ababa, Ethiopia
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Date
2013-11
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Addis Ababa University
Abstract
Introduction:-Reference intervals are ranges of upper and lower limits outside of which values
would be considered abnormal. It depends on the type of instrument and reagents, the principle
or method and the type of population being served. Therefore it is obvious that it should be
established for every population in different regions even within a country.
Objective:-The aim of this study is to establish population specific reference intervals of thyroid
stimulating hormone, free thyroxine and free triidothyronine levels of cord blood.
Materials and methods፡- A cross sectional study was conducted from July, 2013 to November,
2013 using cord blood sample from 123 new born infants of both sexes born at Tikur Anbessa
Teaching Specialized Hospital and Gandhi Memorial Hospital. Thyroid stimulating hormone,
free thyroxine and free triidothyronine were measured using Elecsys 2010 immunoassay
analyzer at Ethiopian Health and Nutrition Research Institute. The non-parametric method of
reference range determination was used.
Results:- 123 Cord blood samples collected from umbilical cord of newborns were analyzed for
thyroid stimulating hormone, free thyroxine and free triidothyronine values. The birth weights
ranged between 2500g to 4700g with mean (SD) value of 3241.46(459.495)gram. Their
gestational age ranged between 37 to 44 weeks with an average of 39.74 weeks. The 2.5th and
97.5th percentiles of
values were found to be 3.48 mIU/L and 27.57 mIU/L for thyroid
stimulating hormone, 0.89 ng/dL and 1.53 ng/dL for free thyroxine and 1.19 pg/mL and 2.51
pg/mL for free triidothyronine respectively.
Conclusion:- In the present study the reference intervals of thyroid stimulating hormone ,free
thyroxine and free triidothyronine were tried to be established and based on the results obtained ,
were 3.48 - 27.56 mIU/L for thyroid stimulating hormone, 0.89 - 1.53 ng/dL for free thyroxine
and 1.19 - 2.51 pg/mL for free triidothyronine. It has been concluded that the result can provide
us with an important clue to establish population specific reference intervals using large scale
studies.
Key words:-Thyroid function tests, reference intervals, screening program, Congenital
hypothyroidism
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Keywords
Thyroid function tests; Reference intervals; Screening program; Congenital hypothyroidism