Science

To understand the plight of the rejected donors you may first need to understand some of what goes on behind the scenes at Canadian Blood Services / Héma Québec

Since approximately 1999 Canadian Blood Services / Héma Québec has used Nucleic Acid Amplification Testing (NAT) to screen blood samples for HIV as well as Hepatitis C and West Nile Virus.¹ Because NAT is an expensive process 24 samples² are pooled together and tested for the three viruses. If the test is negative, all of the blood is safe for use. If the test is positive then the blood is broken up into smaller groups and tested again until the infected blood is found.¹

The next definition you should know is the window period. A window period as defined by Canadian Blood Services / Héma Québec is the time between donor exposure to the virus and the appearance of antibodies. ³ Canadian Blood Services / Héma Québec also states that the window period for current testing is about 16 days³ and scientific journals cite that the window period for detecting HIV with NAT is 8.4 to 15.6 days.⁴

There seems to be little scientific rationale behind banning people for life who are currently disqualified from donating based on questions 19 and 22 of the donor questionnaire. These two questions ban for life any male who has had sexual contact with another male since 1977 or any female who has had sexual contact with a male who fits the same criteria.

External Resources

1. http://www.blood.ca/CentreApps/Internet/UW_V502_MainEngine.nsf/page/NATFAQs?OpenDocument
2. http://www.blood.ca/CentreApps/Internet/UW_V502_MainEngine.nsf/resources/PDF/$file/general_Document.pdf
3. http://www.blood.ca/CentreApps/Internet/UW_V502_MainEngine.nsf/page/Window+Period?OpenDocument
4. Le Corfec, E., Le Pont, F., Tuckwell, H., Rouzioux, C. and Costagliola, D. (1999), Direct HIV testing in blood donations: variation of the yield with detection threshold and pool size. Transfusion, 39: 1141.1144. doi: 10.1046/j.1537-2995.1999.39101141.x