title: Influence of using a roller mixer on rejected samples in coagulation tests.
abstract: BACKGROUND
  The influence of using a roller mixer just after blood collection on the ratio of rejected samples in coagulation tests was investigated retrospectively.
  
  
  METHODS
  Numbers of blood samples collected in centralized units of outpatient clinics for prothrombin time (PT) were 24,050 in group I and 24,500 in group II (H. Aral, unpublished data). In group I, the tubes were inverted manually. In group II, the tubes were left standing on roller mixer with 30 rpm. The ratios of rejected samples of the two groups were compared statistically with ki-square analysis.
  
  
  RESULTS
  Using a roller mixer, rate of rejection decreased from 0.79% (group I) to 0.20% (group II) (P<0.001).
  
  
  CONCLUSIONS
  We suggested using roller mixer to improve the reliability of coagulation testing. Such standardization in preanalytical phase may be helpful in preventing laboratory errors and obtaining correct test results in coagulation tests.
authors.affiliation: Clinical Biochemistry Laboratory, Ministry of Health Istanbul Research and Training Hospital, Istanbul, Turkey. drhalearal@yahoo.com
authors.forename: Hale
authors.initials: H
authors.lastname: Aral
authors.forename: Murat
authors.initials: M
authors.lastname: Usta
mesh_terms: D001780:Blood Coagulation Tests / Q000379:methods* / Q000592:standards; D001800:Blood Specimen Collection / Q000379:methods / Q000592:standards; D019411:Clinical Laboratory Techniques / Q000379:methods* / Q000592:standards; D006801:Humans; D011517:Prothrombin Time; D015203:Reproducibility of Results; D012189:Retrospective Studies