Normal Reference Range for Serum TSH, Free T4, Total T4, and Total T3 on Roche® Platforms in Basrah, Iraq

Adel Gassab Mohammed,Nassar Taha Alibrahim,Rudha Naser Hussein,Ammar Mohammed Saeed Almomin,Samih Abed Odhaib,Haider Ayad Alidrisi,Muayad Baheer Kadhim,Hussein Ali Nwayyir,Mahmood Thamer Altemimi,Husam Jihad Imran,Ibrahim Abbood Zaboon,Dheyaa Kadhim Al-Waeli,Abbas Ali Mansour,Ibrahim Hani Hussein,Ali Hussain Alhamza

doi:10.9734/jpri/2021/v33i45a32727

Abstract

Background: Thyroid function tests are mandatory in clinical practice because symptoms and signs are not reliable to discriminate between various types of thyroid disease. Aim: The aim of this study was to determine assay-specific reference range for serum free T4, total T4, total T3 and TSH among healthy non-pregnant adult cohort for Roche® platforms in Basrah (Southern Iraq) from single laboratory in a tertiary center using indirect approach of the available data. Methods: A Cross sectional study for non-pregnant adults 19 years and above. Sera were analyzed by using cobs e411 for thyroid functions tests. Results: Total enrolled persons were 10,078. The 95% reference intervals for TSH were 0.20-6.50 μIU/mL, which increased with age though not linear, for free T4 were 0.8-1.70 ng/dL, for total T4 were 3.78-15.33 μg/dL, and for total T3 were 0.80-2.50 ng/mL. Colcusion: Cobs e411(Roche® analytical platform) analyzer reference range for thyroid function cannot be applied for Iraqi population .

Highlights

Symptoms and signs are not reliable to discriminate various thyroid disease and we have to rely on thyroid function test
This study represented a large sample for age and gender specific reference intervals for thyroid hormones in apparently health population from Basrah (Southern Iraq) with no previous thyroid disease or thyroid autoimmunity
We found higher TSH, total T4 and total T3 among women than men, while men have higher level of free T4

Summary

Introduction

Symptoms and signs are not reliable to discriminate various thyroid disease and we have to rely on thyroid function test.Factors that affect thyroid hormones level are mainly age, smoking, genetic factors, iodine status but not body mass index (BMI) [1,2,3,4,5,6,7,8,9].there are wide range in reference range for thyroid hormone using different analytical platforms, despite they are using the same automated chemiluminescent immunoassays principles [10].Standardization and harmonization of these assays is ongoing, but still beyond the level to reduce interlaboratory variations.Some advocates measuring TSH and free T4 to assess thyroid function in healthy population and total T4 and TSH to assess thyroid function in those with hypothyroidism or hyperthyroidism [11].Establishing country and analytical platforms specific reference range seems important to ensure local own normal values for thyroid hormones [12]. Symptoms and signs are not reliable to discriminate various thyroid disease and we have to rely on thyroid function test. There are wide range in reference range for thyroid hormone using different analytical platforms, despite they are using the same automated chemiluminescent immunoassays principles [10]. Establishing country and analytical platforms specific reference range seems important to ensure local own normal values for thyroid hormones [12]. Thyroid function tests are mandatory in clinical practice because symptoms and signs are not reliable to discriminate between various types of thyroid disease. Aim: The aim of this study was to determine assay-specific reference range for serum free T4, total T4, total T3 and TSH among healthy non-pregnant adult cohort for Roche® platforms in Basrah (Southern Iraq) from single laboratory in a tertiary center using indirect approach of the available data.

Objectives

Methods

Results

Discussion

Conclusion