title: Effect of blood collection tubes on total triiodothyronine and other laboratory assays.
abstract: BACKGROUND
  Increased total triiodothyronine (TT(3)) assay results in apparently euthyroid patients triggered an investigation of the effect of blood collection tubes on serum TT(3) and other laboratory assays.
  
  
  METHODS
  We examined potential assay interference for three types of tubes: plastic Greiner Bio-One Vacuette; glass Becton Dickinson (BD) Vacutainer; and plastic BD Vacutainer SST tubes. Serum samples from apparently healthy volunteers (age range, 30-60 years; 15 males and 34 females) were collected in different tube types and analyzed in 17 immunoassays (n = 49), 30 clinical chemistry tests (n = 20), and 33 immunology assays (n = 15). Tube effects were also examined by adding pooled serum to different tube types.
  
  
  RESULTS
  TT(3) values, when measured by the IMMULITE 2000 but not the AxSYM analyzer, were significantly higher (P <0.0001) for SST (2.81 nmol/L) than either glass (2.15 nmol/L) or Vacuette (2.24 nmol/L) tubes. The effect was large enough to substantially shift the distribution of patient values, increasing the percentage of values above the reference interval from 11.3% to 35.8%. The degree of interference from SST tubes on TT(3) differed among various tube lots and could be attributed to a tube additive shared by other plastic tubes. Results from several other tests statistically differed among tube types, but differences were not considered to be clinically significant.
  
  
  CONCLUSIONS
  Assay interferences from blood collection tubes represent challenges to clinical laboratories because they are not detected by the usual quality-control or proficiency testing programs. Laboratories can, however, address this problem by monitoring distribution of patients' results.
authors.affiliation: Clinical Chemistry Service, Department of Laboratory Medicine, Warren Grant Magnuson Clinical Center, NIH, Bethesda, MD 20892-1508, USA.
authors.forename: Raffick A R
authors.initials: RA
authors.lastname: Bowen
authors.forename: Yung
authors.initials: Y
authors.lastname: Chan
authors.forename: Joshua
authors.initials: J
authors.lastname: Cohen
authors.forename: Nadja N
authors.initials: NN
authors.lastname: Rehak
authors.forename: Glen L
authors.initials: GL
authors.lastname: Hortin
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Csako
authors.forename: Alan T
authors.initials: AT
authors.lastname: Remaley
mesh_terms: D000328:Adult; D001800:Blood Specimen Collection / Q000295:instrumentation*; D019963:Clinical Chemistry Tests / Q000379:methods*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D008875:Middle Aged; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine