NEW YORK, March 25 (Reuters) -- Health experts say the nation's blood supply is highly safe, but a new study shows that some blood donors still fail to report risk factors that could disqualify them from donation.
These include: injection drug use; sex with a known injection drug user; sex with a man who has ever had sex with another man; prior infection with syphilis or gonorrhea in the past year; and a history of blood transfusion or needle sticks in the past year.
"Individuals who do not respond accurately to questions about infectious disease risk factors at the time of blood donation represent a potential threat to the safety of the blood supply," states Dr. Alan E. Williams and colleagues of the American Red Cross Blood Services, Holland Laboratory in Baltimore, Maryland.
The study, published in this week's issue of The Journal of the American Medical Association, looked at anonymous mail-survey responses from 34,726 donors at blood centers in Detroit, San Francisco, Los Angeles, Oklahoma City, and in the Baltimore/Washington, D.C. area. The questionnaires collected medical, behavioral, ethnic, age, income, and other demographic information.
Among the questions were six that tapped behavioral and other risks that would have been a basis for deferral or temporary disqualification if reported during donor screening interviews at blood centers. A "yes" answer to these "deferrable risks" survey questions called for respondents to check the appropriate box pertaining to the most recent time of the event.
"A total of 186 per 10,000 respondents (1.9%) reported a deferrable risk that was present at the time of their past donation, while 39 per 10,000 (0.4%) reported this behavior within the three months prior to donation," the researchers write.
And a closer look at the responses revealed that men were 1.4 times more likely to report a deferrable risk than women, and first-time donors were 1.6 times more likely to do so, compared with repeat donors.
The study also found that donors who used the confidential unit exclusion option (CUE) were 7.6 times more likely to report a risk in the survey questions. CUE is a call-back procedure that allows donors who believe they are at risk and may have given blood under peer pressure to indicate later that their blood may not be suitable for transfusion.
Moreover, according to the study, laboratory testing for seven infectious disease factors, including HIV antibodies and hepatitis, failed to eliminate a large percentage of donors who reported deferrable risks.
"Our study shows that only 8.2% of those who reported risks were screened out by laboratory testing," the researchers state. "Our study demonstrates a low level of behavioral risk that is not eliminated through the combination of oral questioning, laboratory screening, and CUE procedures."
Still, the Red Cross team notes that the combination of donor screening and laboratory testing has reduced the risk of transmitting HIV through blood transfusion to an estimated current level of 2 per 1 million units of blood.
But they point out that despite the blood supply's current high level of safety, the study indicates a need for further refinement of the blood donor process, including use of the new HIV-antigen test and improvements in donor education and screening materials.
"While the prevalence of deferrable risk factors in blood donors is low, the public health consequences of these observations are substantial considering the fact that 12 million donations... are drawn annually in the United States, and that these risk factors may be associated with a range of transfusion-transmissible agents... not just HIV," state the researchers.
SOURCE: The Journal of the American Medical Association (1997;277:967-972)
