title: Method specific second-trimester reference intervals for thyroid-stimulating hormone and free thyroxine.
abstract: OBJECTIVE
  To determine second trimester reference intervals for TSH and FT4.
  
  
  METHODS
  Samples from 3102 subjects were tested for TPO and Tg antibodies.
  
  
  METHODS
  Elecsys E170 reference intervals for TSH and FT4 were determined using antibody-negative samples.
  
  
  RESULTS
  Second trimester reference intervals for TSH and FT4 were 0.18-4.07 mIU/L and 9.5-15.8 pmol/L, respectively. The Elecsys E170 TSH results were positively biased compared to ARCHITECT i2000(SR) results for these same samples.
  
  
  CONCLUSIONS
  Method-specific reference intervals are required for TSH and FT4.
authors.affiliation: Department of Clinical Laboratory Sciences, Weber State University, Ogden, UT, USA.
authors.forename: Rechelle
authors.initials: R
authors.lastname: Silvio
authors.forename: Karly J
authors.initials: KJ
authors.lastname: Swapp
authors.forename: Sonia L
authors.initials: SL
authors.lastname: La'ulu
authors.forename: Kara
authors.initials: K
authors.lastname: Hansen-Suchy
authors.forename: William L
authors.initials: WL
authors.lastname: Roberts
mesh_terms: D005260:Female; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000378:metabolism*; D012015:Reference Standards; D013972:Thyrotropin / Q000378:metabolism*; D013974:Thyroxine / Q000378:metabolism*
chemical_list: D013972:Thyrotropin; D013974:Thyroxine