title: Performance of chemically modified plastic blood collection tubes.
abstract: OBJECTIVE
  The objective of this study was to compare newly-modified and aged chemoPET tubes, which contain no problematic surfactants, with commercially available serum blood collection tubes (BCTs) for use in analysis of cortisol, total triiodothyronine (TT3), total thyroxine (TT4), and routine clinical chemistry analytes in serum from apparently healthy volunteers and pooled quality control (QC) specimens.
  
  
  METHODS
  Blood specimens collected from 60 apparently healthy volunteers (18 males, 42 females) and pooled QC specimens poured into seven different BCTs were analyzed by a trained phlebotomist. Cortisol, TT3, and TT4 levels were measured on an Immulite 1000 instrument and routine chemistry tests were analyzed on a Siemens RxL instrument. The significance of differences between chemoPET and other BCT types compared to glass tubes were assessed by Student's paired t-test or repeated measures ANOVA or their non-parametric equivalents. The BCT-related biases (deviation from glass tubes) in analyte concentrations were compared with the current desirable allowable bias, derived from biological variation. Serum analyte concentrations in the different BCTs that exceeded their respective significant change limits were considered clinically significant.
  
  
  RESULTS
  No statistically and/or clinically significant differences were noted in the analyte concentrations from serum specimens and pooled QC material when our newly modified and aged chemoPET tubes were compared to glass and other BCTs.
  
  
  CONCLUSIONS
  The chemoPET tubes described here may be a suitable alternative to serum BCTs that contain problematic surfactants known to interfere with some clinical assays on the Immulite 1000 and RxL instruments.
authors.affiliation: Clinical Chemistry Service, Department of Pathology, Stanford University Medical Center, Rm H1507B, Stanford, CA 94305-5627, United States. Electronic address: rbowen@stanfordhealthcare.org.
authors.forename: Raffick A R
authors.initials: RA
authors.lastname: Bowen
authors.affiliation: Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, 1700 4th Street, Byers Hall 304A, San Francisco, CA 94158, United States.
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Kim
authors.affiliation: Clinical Chemistry Service, Department of Pathology, Stanford University Medical Center, Rm H1507B, Stanford, CA 94305-5627, United States.
authors.forename: Annie
authors.initials: A
authors.lastname: Sattayapiwat
authors.affiliation: Clinical Chemistry Service, Department of Pathology, Stanford University Medical Center, Rm H1507B, Stanford, CA 94305-5627, United States.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Austria-Esguerra
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305-5080, United States.
authors.forename: Richard N
authors.initials: RN
authors.lastname: Zare
mesh_terms: D006801:Humans; D018962:Phlebotomy / Q000295:instrumentation*; D011786:Quality Control
keywords: Blood collection tube; Quality control; Surface modification; Thyroxine; Triiodothyronine