title: Correlation between mass and volume of collected blood with positivity of blood cultures.
abstract: BACKGROUND
  The collection of blood cultures is an extremely important method in the management of patients with suspected infection. Microbiology laboratories should monitor blood culture collection.
  
  
  METHODS
  Over an 8-month period we developed a prospective, observational study in an adult Intensive Care Unit (ICU). We correlated the mass contained in the blood vials with blood culture positivity and we also verified the relationship between the mass of blood and blood volume collected for the diagnosis of bloodstream infection (BSI), as well as we explored factors predicting positive blood cultures.
  
  
  RESULTS
  We evaluated 345 patients with sepsis, severe sepsis or septic shock for whom blood culture bottles were collected for the diagnosis of BSI. Of the 55 patients with BSI, 40.0% had peripheral blood culture collection only. BSIs were classified as nosocomial in 34.5%. In the multivariate model, the blood culture mass (in grams) remained a significant predictor of positivity, with an odds ratio 1.01 (i.e., for each additional 1 mL of blood collected there was a 1% increase in positivity; 95% CI 1.01-1.02, p = 0.001; Nagelkerke R Square [R(2)] = 0.192). For blood volume collected, the adjusted odds ratio was estimated at 1.02 (95% CI: 1.01-1.03, p < 0.001; R(2) = 0.199). For each set of collected blood cultures beyond one set, the adjusted odds ratio was estimated to be 1.27 (95% CI: 1.14-1.41, p < 0.001; R(2) = 0.221).
  
  
  CONCLUSIONS
  Our study was a quality improvement project that showed that microbiology laboratories can use the weight of blood culture bottles to determine if appropriate volume has been collected to improve the diagnosis of BSI.
authors: Intensive Care Unit, Hospital Israelita Albert Einstein, São Paulo, Brazil. lariessa.neves@einstein.br.
authors: Lariessa
authors: L
authors: Neves
authors: Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil. alexandre.marra@einstein.br.|Division of Medical Practice, Hospital Israelita Albert Einstein, Av. Albert Einstein, 627/701, 1st floor, Room 108, Bloco A1, Morumbi, São Paulo, 05651-901, Brazil. alexandre.marra@einstein.br.
authors: Alexandre Rodrigues
authors: AR
authors: Marra
authors: Intensive Care Unit, Hospital Israelita Albert Einstein, São Paulo, Brazil. thiago.camargo@einstein.br.
authors: Thiago Zinsly Sampaio
authors: TZ
authors: Camargo
authors: Intensive Care Unit, Hospital Israelita Albert Einstein, São Paulo, Brazil. maura.santos@einstein.br.
authors: Maura Cristina
authors: MC
authors: dos Santos
authors: Intensive Care Unit, Hospital Israelita Albert Einstein, São Paulo, Brazil. flavia.zulin@einstein.br.
authors: Flávia
authors: F
authors: Zulin
authors: Intensive Care Unit, Hospital Israelita Albert Einstein, São Paulo, Brazil. patricia.csilva@einstein.br.
authors: Patrícia Candido
authors: PC
authors: da Silva
authors: Intensive Care Unit, Hospital Israelita Albert Einstein, São Paulo, Brazil. natalia.moura@einstein.br.
authors: Natália Ariede
authors: NA
authors: de Moura
authors: Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil. elivane.victor@einstein.br.
authors: Elivane da Silva
authors: Eda S
authors: Victor
authors: Department of Microbiology, Hospital Israelita Albert Einstein, São Paulo, Brazil. jacyr.pasternak@einstein.br.
authors: Jacyr
authors: J
authors: Pasternak
authors: Division of Medical Practice, Hospital Israelita Albert Einstein, Av. Albert Einstein, 627/701, 1st floor, Room 108, Bloco A1, Morumbi, São Paulo, 05651-901, Brazil. oscar@einstein.br.
authors: Oscar Fernando Pavão
authors: OF
authors: dos Santos
authors: Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA, USA. medmond@mcvh-vcu.edu.
authors: Michael B
authors: MB
authors: Edmond
authors: Department of Microbiology, Hospital Israelita Albert Einstein, São Paulo, Brazil. marines.martino@einstein.br.
authors: Marines Dalla Valle
authors: MD
authors: Martino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification; D001769:Blood / Q000382:microbiology; D005260:Female; D005658:Fungi / Q000145:classification / Q000302:isolation & purification; D006801:Humans; D008297:Male; D008875:Middle Aged; D018805:Sepsis / Q000097:blood* / Q000382:microbiology; D013048:Specimen Handling