Trends in Scottish newborn screening programme for congenital hypothyroidism 1980-2014: Strategies for reducing age at notification after initial and repeat sampling

Abstract

Objectives: To determine ages at first capillary sampling and notification and age at notification after second sampling in Scottish newborns referred with elevated thyroid-stimulating hormone (TSH). Subjects and methods: Referrals between 1980 and 2014 inclusive were grouped into seven 5-year blocks and analysed according to agreed standards. Results: Of 2 116 132 newborn infants screened, 919 were referred with capillary TSH elevation ≥8 mU/L of whom 624 had definite (606) or probable (18) congenital hypothyroidism. Median age at first sampling fell from 7 to 5 days between 1980 and 2014 (standard 4-7 days), with 22, 8 and 3 infants sampled >7 days during 2000-2004, 2005-2009 and 2010-2014. Median age at notification was consistently ≤14 days, range falling during 2000-2004, 2005-2009 and 2010-2014 from 6 to 78, 7-52 and 7-32 days with 12 (14.6%), 6 (5.6%) and 5 (4.3%) infants notifed >14 days. However 18/123 (14.6%) of infants undergoing second sampling from 2000 onwards breached the ≤26-day standard for notification. By 2010-2014, the 91 infants with confirmed congenital hypothyroidism ha shown favourable median age at first sample (5 days) with start of treatment (10.5 days) approaching age at notification. Conclusion: Most standards for newborn thyroid screening are being met by the Scottish programme, but there is a need to reduce age range at notification, particularly following second sampling. Strategies to improve screening performance include carrying out initial capillary sampling as close to 96 hours as possible; introducing 6-day laboratory reporting and use of electronic transmission for communicating repeat requests.