title: Blood spots as an alternative to whole blood collection and the effect of a small monetary incentive to increase participation in genetic association studies.
abstract: BACKGROUND
  Collection of buccal cells from saliva for DNA extraction offers a less invasive and convenient alternative to venipuncture blood collection that may increase participation in genetic epidemiologic studies. However, dried blood spot collection, which is also a convenient method, offers a means of collecting peripheral blood samples from which analytes in addition to DNA can be obtained.
  
  
  METHODS
  To determine if offering blood spot collection would increase participation in genetic epidemiologic studies, we conducted a study of collecting dried blood spot cards by mail from a sample of female cancer cases (n = 134) and controls (n = 256) who were previously selected for a breast cancer genetics study and declined to provide a venipuncture blood sample. Participants were also randomized to receive either a $2.00 bill or no incentive with the blood spot collection kits.
  
  
  RESULTS
  The average time between the venipuncture sample refusal and recruitment for the blood spot collection was 4.4 years. Thirty-seven percent of cases and 28% of controls provided a dried blood spot card. While the incentive was not associated with participation among controls (29% for $2.00 incentive vs. 26% for no incentive, p = 0.6), it was significantly associated with participation among the breast cancer cases (48% vs. 27%, respectively, p = 0.01). There did not appear to be any bias in response since no differences between cases and controls and incentive groups were observed when examining several demographic, work history and radiation exposure variables.
  
  
  CONCLUSIONS
  This study demonstrates that collection of dried blood spot cards in addition to venipuncture blood samples may be a feasible method to increase participation in genetic case-control studies.
authors.affiliation: Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. pbhatti@fhcrc.org
authors.forename: Parveen
authors.initials: P
authors.lastname: Bhatti
authors.forename: Diane
authors.initials: D
authors.lastname: Kampa
authors.forename: Bruce H
authors.initials: BH
authors.lastname: Alexander
authors.forename: Christopher
authors.initials: C
authors.lastname: McClure
authors.forename: Danny
authors.initials: D
authors.lastname: Ringer
authors.forename: Michele M
authors.initials: MM
authors.lastname: Doody
authors.forename: Alice J
authors.initials: AJ
authors.lastname: Sigurdson
mesh_terms: D001782:Blood Donors / Q000523:psychology*; D001800:Blood Specimen Collection / Q000191:economics / Q000379:methods*; D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D016015:Logistic Models; D018579:Patient Selection; D018962:Phlebotomy / Q000523:psychology