title: Variability in thyroid function test requests across general practices in south-west England.
abstract: BACKGROUND
  The number of thyroid function tests (TFTs) performed in the UK and other countries has increased considerably in recent years. Inconsistent clinical practice associated with inappropriate requests for tests is thought to be an important cause for this increase.
  
  
  OBJECTIVE
  To study the extent of variability in requests for TFTs from general practices.
  
  
  METHODS
  We analysed routine data on all TFTs on patients aged 16 years and over carried out by two hospitals in south-west England (Royal Cornwall Hospital and Royal Devon & Exeter Hospital) during 2010 at the request of 107 general practices.
  
  
  RESULTS
  A total of 195 309 TFT requests were made for 148 412 patients (63% female). The total requests included 192 108 tests for thyroid-stimulating hormone (TSH), 43 069 for free thyroxine (FT4) and 1972 for free tri-iodothyronine (FT3). The number of TSH tests per 1000 list size varied widely across the practices, ranging from 84 to 482. Most of the variation was due to heterogeneity across practices and only 24% of this was accounted for by prevalence of hypothyroidism and socio-economic deprivation.
  
  
  CONCLUSIONS
  There is wide variation in TFT requests from general practice and scope to reduce both unnecessary TFTs and the variability in the clinical practice. Further studies are required to understand the causes for the variability in testing thyroid function.
authors: Department of Endocrinology, Royal Devon & Exeter Hospital, Exeter, UK. b.vaidya@exeter.ac.uk
authors: Bijay
authors: B
authors: Vaidya
authors: Obioha C
authors: OC
authors: Ukoumunne
authors: Joanna
authors: J
authors: Shuttleworth
authors: Alan
authors: A
authors: Bromley
authors: Aled
authors: A
authors: Lewis
authors: Chris
authors: C
authors: Hyde
authors: Anthea
authors: A
authors: Patterson
authors: Simon
authors: S
authors: Fleming
authors: Julie
authors: J
authors: Tomlinson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004739:England / Q000453:epidemiology; D005194:Family Practice; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D015203:Reproducibility of Results; D013959:Thyroid Diseases / Q000175:diagnosis* / Q000453:epidemiology; D013960:Thyroid Function Tests / Q000592:standards*