1. Introduction

Iodine deficiency disorders has been one of the targets for elimination by the World Health Organization (WHO) throughout the world. It is a nutritional related disease which is preventable through adequate iodine supplementation. Iodine facilitates optimal brain development

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

in fetuses and it is involved in the synthesis of thyroid hormones, one of the vital hormones in human body. Hence, with optimum iodine supplementation, it could lead towards more intelligent population.

intelligent generation to come since it was reported that babies with higher intelligent quotient (IQ) were born from mothers with adequate iodine nutrition during pregnancy [3]. Iodine deficiency may also affect the production of thyroid hormones since each of them need iodine to be covalently bound to the tyrosine backbone [4]. Lack of thyroid hormone production may lead to hypothyroidism and may affect many metabolisms in human body [5]. Thus, iodine is very vital

Understanding Quality Control with Urinary Iodine Estimation

http://dx.doi.org/10.5772/intechopen.74442

69

IDD elimination program is carried out worldwide. Various interventions of iodine have been implemented including through iodized water and iodized salt. Intervention of iodized salt is the most cost-effective strategy in the elimination program. Iodized salt interventions require only investment of 5–10 cents/year per person [6]. In 20 years, iodization of salt had reduced the prevalence of IDD, whereby, in the year 1993, the number of 131 iodine-deficient had been reduced to only 31 countries in the year 2014. In 2014 also, 70% households had access to adequately iodized salt. Within the years 2009–2013, it was estimated that 50–86% of households are consuming adequately iodized salt, ranging from the least developed countries to

1.3. IDD monitoring and determination of median urinary iodine of population

Urinary iodine testing is mandatory before any intervention implementation and in monitoring the universal salt iodization (USI) programs. Urinary iodine laboratories are responsible to perform the urinary iodine testing on respondent samples in determining the population median values. Even though the target group to determine median urinary iodine is schoolchildren aged 8–10 years old, various researches were also done on pregnant women and followed up with their babies to investigate the relationship between iodine status during pregnancy and the babies' IQ [3]. Thus, quality control throughout the laboratory performance is of utmost importance to ensure that the results obtained are valid and reliable to generate

The urinary iodine laboratories (there are five laboratories in the country) were formed under the National IDD Eradication Program parallel with the initiative by the World Health Organization (WHO) for eliminating IDD worldwide. Quality management has been practiced throughout the Ministry of Health following the twelve elements outlined by WHO [8] (Figure 2). However, in this chapter, only the quality control aspects related to the urinary iodine laboratory quality

management will be discussed, mainly on the processes related to the analysis.

to human growth and development.

1.2. IDD elimination program

East Asia and Pacific countries [7].

2. Quality in urinary iodine laboratories

2.1. Quality management system

accurate reports.

Urinary iodine is the test in determining the baseline of a population's iodine nutrition before decision of implementing Universal Salt Iodization (USI) is made. It is also important to monitor the iodine nutrition of the population after USI has been implemented. Sampling for urinary iodine testing among school children is non-invasive and urinary iodine is a reliable biomarker for immediate iodine level in one's body. Although thyroglobulin is the biomarker for long-term iodine nutrition in a human, urinary iodine remains the chosen biomarker for the purpose of easier and cheaper way of estimation of iodine nutrition status worldwide. In ensuring the validity of urinary iodine tests results, quality control has to be implemented in the laboratory. In the subsequent sections of this chapter, the quality control plans and implementation are discussed for the benefit of urinary iodine laboratory managers and operators.
