title: Quality assurance in blood culture: A retrospective study of blood culture contamination rate in a tertiary hospital in Nigeria.
abstract: BACKGROUND
  Blood culture is a critical tool for diagnosing septicaemia. Quite frequently, contamination of blood sample poses a great challenge to accurate diagnosis. This study evaluated the rate of blood culture contamination in our hospital over a one-year period.
  
  
  METHODS
  It was a retrospective study of 1032 blood cultures carried out in a clinical laboratory of a tertiary hospital in North Central part of Nigeria between 2010 and 2011.
  
  
  RESULTS
  There were 730 blood cultures from paediatric and 302 adult patients. The overall yield was 22%; 107 out of the 730 were contaminated giving a contamination rate of 10.4%. Contamination rate was higher in children than in adult (11% vs 8%) specimen. These rates were much higher than the acceptable benchmark of 2-3%. The main contaminants were coagulase negative Staphylococcus, Bacillus species, Diphtheroids and Enterococcus species.
  
  
  CONCLUSIONS
  Contamination rate is high, and mainly due to normal skin flora, suggesting aseptic collection challenges as the main cause. We recommend a review of the entire process of blood collection for culture and analysis with a view to instituting appropriate quality assurance measures to reduce the contamination rate.
authors.affiliation: Department of Medical Microbiology and Parasitology, National Hospital Abuja, Abuja, Nigeria.
authors.forename: Iregbu Kenneth
authors.initials: IK
authors.lastname: Chukwuemeka
authors.affiliation: Department of Medical Microbiology and Parasitology, National Hospital Abuja, Abuja, Nigeria.
authors.forename: Yakubu
authors.initials: Y
authors.lastname: Samuel
keywords: Blood culture; contamination; quality assurance