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Objectives: To analyze data from the Scottish capillary thyroid stimulating hormone (TSH) screening program for hypothyroidism in Down syndrome to identify a threshold for capillary TSH elevation below which low venous free thyroxine (fT4) (<9 pmol/L) and/or frank venous TSH elevation (>10 mU/L) range is unlikely., Study Design: Review of proformas prospectively submitted on all children with Down syndrome referred via the screening program between 2003 and 2013., Results: Ninety-nine patients with Down syndrome (50 females, 49 males) were identified, 76 school-age (≥ 5 years) and 23 preschool (<5 years), mean (range) age at referral 9.4 (0.9-18.1) years. Pearson correlation between capillary TSH and venous TSH was 0.814; between capillary TSH and venous fT4 -0.522 (P = .01). Receiver operator curve analysis showed that capillary TSH values of 4 and 6 mU/L were 95.9% and 73.5% sensitive, 5.8% and 80.8% specific, respectively, in predicting venous TSH >10 mU/L. Fifty-three children had capillary TSH values of 4-5.9 mU/L of whom only one, a boy of 15.8 years, had subnormal venous fT4 (<9 pmol/L), and venous TSH >10 mU/L was found in 13 (4 preschool)., Conclusions: Venous fT4 is normal in almost all patients with Down syndrome with capillary TSH 4-6 mU/L. We propose an algorithm incorporating rescreening by finger prick after 6 months, rather than venepuncture, in school-aged children with borderline capillary TSH elevation. Further data are needed before this approach can be recommended for preschool children., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objectives: To assess uptake of community-based capillary thyroid stimulating hormone (TSH) screening in Scotland and determine the optimal frequency of screening, the justification for preschool screening and strategies for treatment., Methods: Subjects with Down's syndrome aged 1-19 years underwent capillary TSH measurement. Clinical and biochemical data were collected using proformas., Results: 5742 capillary TSH tests were performed on 1329 children in 1997-2009, increasing from 183 children from two health boards tested in 1997 to 630 from 13 health boards tested in 2009. Of 132 children referred by the screening laboratory with elevated capillary TSH, 98 (M:F ratio 1:1.2, median (range) age 8.9 (0.9-17.9) years) had adequate documentation and 76 had thyroid dysfunction (defined as venous TSH >6 mU/l), giving a prevalence of not less than 5.7%. Fifty-six (57%) had tested negative during the previous year, 8 (8%) tested positive on their first screening test and 23/67 (34%) were thyroid peroxidase autoantibody negative on initial venous blood. Two of the 13 (13%) preschool children were severely hypothyroid (venous TSH 71 and 283 mU/l). Of patients with venous TSH 6-10.9 (n=27), 11.0-20.9 (n=25) and ≥ 21.0 mU/l (n=24) following referral, initial/subsequent treatment with thyroxine was given in 3/8, 15/5 and 21/1, respectively., Conclusion: Capillary TSH screening in Down's syndrome is eminently feasible and should be performed annually from 1 year of age. Nearly all subjects with initial venous TSH ≥ 11.0 mU/l will require thyroxine treatment but most with TSH 6-10 mU/l only require surveillance initially.

Aims and Methods: Thyroid function tests were initially carried out on 122 children with Down's syndrome aged 6-14 years and then repeated four to six years later in 103 adolescents (85% of the group of 122) when they were aged 10-20 years (median 14.4 years). At the second test two were hypothyroid and two with isolated raised thyroid stimulating hormone (IR-TSH) were receiving thyroxine., Results: At the first test there were 98 (80%) euthyroid children: 83 were retested and four (5%) had IR-TSH. At the first test 24 had IR-TSH: 20 were retested and 14 (70%) had become normal. Seventeen with IR-TSH on initial testing had a thyrotrophin releasing hormone test within three months; TSH had become normal in eight (47%) of these children. There was no association between reported clinical symptoms and IR-TSH, but there were clear symptoms in one of the two with definite hypothyroidism., Conclusions: The likelihood ratio for a positive result on second testing when raised TSH and positive antibody status on first testing are combined is 20. This suggests initial testing results could be used as a basis to select a subgroup for further testing at say five yearly intervals unless new symptoms emerge in the interim. It also suggests that yearly screening (as recommended by the American Academy of Pediatrics, 2001) is probably not justified in the first 20 years of life.

Objective: To determine the feasibility of annual hypothyroid screening of children with Down's syndrome by measuring thyroid stimulating hormone (TSH) on dried blood spots at school, and to describe the outcome in positive children., Design: Establishment of a register of school children with Down's syndrome, and procedures for obtaining permission from parents, annual capillary blood samples, TSH measurement, and clinical assessment of children with TSH values > 10 mU/litre., Subjects: All school age children with Down's syndrome within Lanarkshire and Glasgow Health Boards during 1996-7 and 1997-8., Results: 200 of 214 school children with Down's syndrome were screened. Four of the unscreened children were receiving thyroxine treatment, and only 5 remained unscreened by default. 15 of the 200 children had capillary TSH > 10 mU/litre, and all but 1 had evidence of Hashimoto's thyroiditis. Seven of the 15 children started thyroxine treatment immediately, 6 with a pronounced rise in venous TSH and subnormal free thyroxine (fT4), and one with mildly raised TSH and normal fT4 but symptoms suggesting hypothyroidism. Eight children with mildly raised venous TSH and normal fT4 were left untreated; 1 year after testing positive, fT4 remained > 9 pmol/litre in all cases, but 4 children were started on thyroxine because of a rise in TSH. TSH fell in 3 of the 4 remaining children and there was a marginal rise in 1; all remain untreated. The prevalence of thyroid disease in this population is >/= 8.9%., Conclusion: Dried blood spot TSH measurement is effective for detecting hypothyroidism in Down's syndrome and capillary sampling is easily performed at school. The existing programme could be extended to the whole of Scotland within a few years.