Evaluation of the revised New Zealand national newborn screening protocol for congenital hypothyroidism

• Published in: Clinical endocrinology (Oxford) 2017-03, Vol.86 (3), p.431-437
• Main Authors: Heather, Natasha L., Hofman, Paul L., Hora, Mark, Carll, Joan, Derraik, José G.B., Webster, Dianne
• Format: Article
• Language: English
• Subjects: Clinical Protocols; Congenital diseases; Congenital Hypothyroidism - diagnosis; Congenital Hypothyroidism - epidemiology; Humans; Hypothyroidism; Infant, Newborn; Medical screening; Neonatal Screening - methods; Neonatal Screening - standards; New Zealand; Newborn babies; Reference Values; Thyrotropin - blood; Thyrotropin - standards
• ISSN: 0300-0664; 1365-2265
• DOI: 10.1111/cen.13250

Summary Objective The aim of this study was to assess the performance of the revised New Zealand (NZ) newborn screening TSH cut‐offs for congenital hypothyroidism (CHT). Methods Screening data over 24 months were obtained from the NZ newborn metabolic screening programme, which utilizes a 2‐tier system of direct clinical referral for infants with markedly elevated TSH, and second samples from those with mild TSH elevation. We evaluated the impact of a reduced TSH threshold (50 to 30 mIU/l blood) for direct notification and a lower cut‐off (15 to 8 mIU/l blood) applied to second samples and babies older than 14 days. Results In 2013 and 2014, 117 528 infants underwent newborn screening for CHT. Fifty‐two CHT cases were identified by screening (47 general newborn population, five repeat testing in low‐birth‐weight infants) and one case was missed. Thirty‐two infants with screening TSH ≥30 mIU/l were directly referred at a median of 9 days (5–14) and 15 with TSH 15–29 mIU/l were referred after a second sample at a median of 20 days (9–52, P