GB 16005-2025Determination and classification of the endemic areas of iodine deficiency disorders (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents". Drafting. This document replaces GB 16005-2009 "Classification of Iodine Deficiency Disorders Areas". Compared with GB 16005-2009, the main differences are structural adjustments and editorial changes. Aside from the modifications, the main technical changes are as follows:

---The definition of iodine deficiency disorders has been revised (see 3.1,.2009 version 3.1);

---The delineation units for iodine deficiency disorder areas have been changed (see Chapter 4, Chapter 4 of the.2009 edition);

---The technical indicators for ward delineation have been changed (see Chapter 4, Chapter 4 of the.2009 edition);

---The sampling method has been changed (see Appendix A,

6.1.2 of the.2009 edition). Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents. This document was proposed and is under the jurisdiction of the National Center for Disease Control and Prevention. The release history of this document and the document it replaces is as follows:

---First published as GB 16005-1995 in.1995, and revised for the first time in.2009;

---This is the second revision. Iodine deficiency disorder zone identification and classification

1 Scope

GB 16005-2025 revises the criteria for iodine deficiency endemic areas and, as its title change signals, separates two questions the 2009 text ran together: first whether an area is endemic at all, then which type it is. It sets the determination and the classification, with a normative annex on sampling. The revision matters because China's problem has shifted - after decades of universal salt iodisation the concern in some areas is now excess rather than deficiency, and the criteria have to distinguish them. Issued on 5 October 2025, it takes effect on 1 November 2026, replacing GB 16005-2009. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the edition it replaces are taken from there. The clause text, the tables and the numeric limits are not reproduced on this page - they are in the document itself, which is delivered in full in English translation.

This document specifies the indicators for the identification and classification of iodine deficiency disease areas and describes the corresponding identification methods. This document applies to the identification and classification of iodine deficiency disease areas.

2 Collection and Preservation of Water Samples

GB/T 5750.5 Standard Examination Methods for Drinking Water - Part

5.Inorganic Non-metallic Indicators WS/T 104 Diagnosis of Endemic Cretinism and Endemic Subclinical Cretinism WS/T 107.1 Determination of iodine in urine - Part

1.Arsenic-cerium catalytic spectrophotometry WS/T 107.2 Determination of iodine in urine - Part

2.Inductively coupled plasma mass spectrometry WS/T 10027 Diagnosis of Endemic Goiter

3 Terms and Definitions

The following terms and definitions apply to this document.

3.1 Iodine deficiency in the natural environment leads to a group of diseases and harms caused by iodine malnutrition in the body.

Note. This includes endemic goiter, endemic cretinism, endemic subclinical cretinism, as well as miscarriage, premature birth, stillbirth, and congenital malformations caused by iodine deficiency.

4.Iodine deficiency disorder endemic area identification The survey should be conducted at the administrative village (community) level, following the sampling method specified in Appendix A, and data should be collected and preserved in accordance with GB/T 5750.2. Water samples were analyzed for iodine content according to GB/T 5750.5; urine iodine content was analyzed according to WS/T 107.1 or WS/T 107.2; and so on. WS/T 10027 is used for the diagnosis of endemic goiter; WS/T 104 is used for the diagnosis of endemic cretinism. In areas where the median iodine concentration in drinking water is less than 40 µg/L, areas meeting either

c) are classified as iodine deficiency disease areas.

a) There are new cases of endemic cretinism;

b) Goiter rate. The goiter rate in children aged 8 to 10 years is greater than or equal to 5%;

c) Urinary iodine. The median urinary iodine level in children aged 8 to 10 years was less than 100 µg/L, and the number of samples with a median urinary iodine level less than 50 µg/L was greater than 20%.

5.Classification of Iodine Deficiency Disorder Areas The classification criteria for iodine deficiency disease areas are shown in Table 1.