title: Defining the Newborn Blood Spot Screening Reference Interval for TSH: Impact of Ethnicity.
abstract: There is variability in the congenital hypothyroidism (CH) newborn screening TSH cutoff across the United Kingdom.
  
  
  
  To determine the influences of year, gender, and ethnicity on screening variability and examine whether there is an optimal operational TSH cutoff.
  
  
  
  Single center, retrospective population study using blood spot TSH cards received by the Great Ormond Street Hospital Screening Laboratory between 2006 and 2012.
  
  
  
  A total of 824 588 newborn screening blood spot TSH cards.
  
  
  
  Blood spot TSH results were recorded with demographic data including the Ethnic Category Code.
  
  
  
  The proportions of samples exceeding different TSH cutoffs, ranked by ethnicity.
  
  
  
  The proportion of samples exceeding the TSH cutoff increased over time, with the cutoff at 4 mU/L, but not at 6 mU/L. There was a consistent trend with ethnicity, irrespective of cutoff, with the odds ratio of exceeding the TSH cutoff lowest (∼1.0) in White babies, higher in Pakistani and Bangladeshi (>2.0), and highest in Chinese (>3.5).
  
  
  
  The blood spot TSH screening data demonstrate a clear ranking according to ethnicity for differences in mean TSH. This suggests that there may be ethnic differences in thyroid physiology. Ethnic diversity within populations needs to be considered when establishing and interpreting screening TSH cutoffs.
authors.affiliation: Department of Endocrinology (C.P., S.L., P.H.), and Chemical Pathology, Laboratory Medicine (I.B., S.H., A.I.), Great Ormond Street Hospital, London WC1N 3JH, United Kingdom; and Population, Policy, and Practice Programme (T.J.C.), UCL Institute of Health, London WC1N 1EH, United Kingdom.
authors.forename: Catherine
authors.initials: C
authors.lastname: Peters
authors.affiliation: Department of Endocrinology (C.P., S.L., P.H.), and Chemical Pathology, Laboratory Medicine (I.B., S.H., A.I.), Great Ormond Street Hospital, London WC1N 3JH, United Kingdom; and Population, Policy, and Practice Programme (T.J.C.), UCL Institute of Health, London WC1N 1EH, United Kingdom.
authors.forename: Ivan
authors.initials: I
authors.lastname: Brooke
authors.affiliation: Department of Endocrinology (C.P., S.L., P.H.), and Chemical Pathology, Laboratory Medicine (I.B., S.H., A.I.), Great Ormond Street Hospital, London WC1N 3JH, United Kingdom; and Population, Policy, and Practice Programme (T.J.C.), UCL Institute of Health, London WC1N 1EH, United Kingdom.
authors.forename: Simon
authors.initials: S
authors.lastname: Heales
authors.affiliation: Department of Endocrinology (C.P., S.L., P.H.), and Chemical Pathology, Laboratory Medicine (I.B., S.H., A.I.), Great Ormond Street Hospital, London WC1N 3JH, United Kingdom; and Population, Policy, and Practice Programme (T.J.C.), UCL Institute of Health, London WC1N 1EH, United Kingdom.
authors.forename: Adeboye
authors.initials: A
authors.lastname: Ifederu
authors.affiliation: Department of Endocrinology (C.P., S.L., P.H.), and Chemical Pathology, Laboratory Medicine (I.B., S.H., A.I.), Great Ormond Street Hospital, London WC1N 3JH, United Kingdom; and Population, Policy, and Practice Programme (T.J.C.), UCL Institute of Health, London WC1N 1EH, United Kingdom.
authors.forename: Shirley
authors.initials: S
authors.lastname: Langham
authors.affiliation: Department of Endocrinology (C.P., S.L., P.H.), and Chemical Pathology, Laboratory Medicine (I.B., S.H., A.I.), Great Ormond Street Hospital, London WC1N 3JH, United Kingdom; and Population, Policy, and Practice Programme (T.J.C.), UCL Institute of Health, London WC1N 1EH, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Hindmarsh
authors.affiliation: Department of Endocrinology (C.P., S.L., P.H.), and Chemical Pathology, Laboratory Medicine (I.B., S.H., A.I.), Great Ormond Street Hospital, London WC1N 3JH, United Kingdom; and Population, Policy, and Practice Programme (T.J.C.), UCL Institute of Health, London WC1N 1EH, United Kingdom.
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Cole
mesh_terms: D015415:Biomarkers / Q000097:blood; D003409:Congenital Hypothyroidism / Q000097:blood* / Q000175:diagnosis* / Q000208:ethnology; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening / Q000379:methods*; D011379:Prognosis; D012016:Reference Values; D012189:Retrospective Studies; D013974:Thyroxine / Q000097:blood*
chemical_list: D015415:Biomarkers; D013974:Thyroxine