Title page
Contents
1.0. Introduction 6
1.1. Background 6
1.2. Scope and purpose 6
1.3. Scientific background to the screening protocol 7
1.4. General organisation 9
2.0. The screening protocol 10
2.1. The screening protocol 10
2.2. Sibling testing 11
2.3. Unscreened babies 12
2.3.1. Notification form 12
2.4. Previously screened babies with subsequent discrepant result 12
3.0. Pre-analytical factors 13
3.1. Family history and other risk factors 13
3.2. Specimen requirements 13
3.3. Factors affecting the screening result 13
3.3.1. Potential for false negative results 13
3.3.2. Potential for false positive 14
4.0. The TSH assay 16
4.1. Internal quality and performance monitoring 16
4.2. External quality assessment 16
4.3. Stability of TSH in blood spots 16
4.4. Rationale and definition of TSH cut-offs 16
Analytical cut-off 16
Action cut-off 17
5.0. The first screening specimen 18
5.1. Results from duplicate re-assay 18
5.2. Insufficient sample: no re-assay possible 18
5.3. Only one re-assay possible 18
6.0. The second specimen (i.e. repeat TSH test) 20
6.1. Reason for repeat sample(s) 20
6.2. Action on repeat sample(s) 20
7.0. Preterm Repeat Policy 22
7.1. Policy 22
8.0. Clinical follow-up and referral 24
8.1. Responsibility for communications / clinical liaison 24
8.2. Follow-up of CHT suspected cases 24
8.3. Communication of CHT suspected 25
9.0. Reporting and communication of results 26
9.1. Status codes 26
10.0. Laboratory standards and guidelines 28
10.1. Generic standards 28
10.2. Screening laboratory 28
Organisation 28
Analytical processes 29
10.3. Overall performance 29
Timeliness 29
Quality assurance 29
11.0. Data collection and audit 30
References 31
Acknowledgments 33
Appendix 1. CHT Initial Clinical Referral Standards and Guidelines (January 2013) 34
Appendix 2. British Paediatric Surveillance Unit (BPSU) study - UK Surveillance of Primary Congenital Hypothyroidism in Children Aged 5 Years and Under (UK CHT) 41
Appendix 3. Communication Guidelines: When Congenital Hypothyroidism is Suspected 42
Appendix 4. Template for notification of presumptive positive for designated paediatrician (by screening laboratory to clinician) 44
Table 1. Status codes for CHT 27
Figure 1. Congenital Hypothyroidism - Aetiology 7
Figure 2. CHT screening protocol 11
Figure 3. CHT Preterm Repeat Policy Algorithm 23