title: Blood donors with positive direct antiglobulin tests are at increased risk for cancer.
abstract: BACKGROUND
  Positive direct antiglobulin tests (DATs) have been associated with both autoimmunity and lymphoproliferative disorders. However, it is unknown whether DAT+ in healthy blood donors is associated with an increased risk of malignancies.
  
  
  METHODS
  In the current study, all blood donors with DAT+ samples were identified during the years 1999 through 2003 through the Magen David Adom National Blood Services in Israel. This study compared the risk of cancer among 586 DAT+ and 2344 DAT- donors who were matched according to sex, age, and year of donation. The risk of cancer in DAT+ donors was also compared to expected rates in the general Israeli population. Cancer was ascertained through the Israel Cancer Registry.
  
  
  RESULTS
  Malignancies occurred among 17 (2.9%) of the DAT+ and 27 (1.2%) of the DAT- blood donors; of these, 3 donors in the DAT+ group were diagnosed with hematopoietic malignancies within 12 months of their donation. Even after excluding these early cases, the relative risk of developing cancer was 2.14 (95% confidence interval [CI], 1.13-4.10) comparing DAT+ with DAT- donors, while the relative risk for hematopoietic cancer was 8.3 (95% CI, 1.5-43.2). Comparing DAT+ blood donors with the general population, the standardized incidence ratios (observed/expected cases) were elevated at 2.11 (95% CI, 1.15-3.54; p = 0.16) for all malignancies and 8.03 (95% CI, 2.2-20.6; p = 0.003) for hematologic malignancies.
  
  
  CONCLUSIONS
  There is evidence of a significantly increased risk of cancer, especially hematologic malignancies, among blood donors with a positive DAT even within a short follow-up period.
authors.affiliation: Department of Oncology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel. ryakir@hadassah.org.il
authors.forename: Yakir
authors.initials: Y
authors.lastname: Rottenberg
authors.forename: Vered
authors.initials: V
authors.lastname: Yahalom
authors.forename: Eilat
authors.initials: E
authors.lastname: Shinar
authors.forename: Micha
authors.initials: M
authors.lastname: Barchana
authors.forename: Bella
authors.initials: B
authors.lastname: Adler
authors.forename: Ora
authors.initials: O
authors.lastname: Paltiel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001782:Blood Donors; D003298:Coombs Test; D005260:Female; D019337:Hematologic Neoplasms / Q000175:diagnosis; D006801:Humans; D007557:Israel / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012306:Risk; D055815:Young Adult