- Incidence is per 100,000 person years: ranges:
    HCV 2.83 - 6.87
    HIV 2.22 - 4.76
    HBV 6.74 - 13.42
    HTLV 0.51 - 1.98
- Incidence rates of these markers in the donor population are substantially less than the incidence rates found in the general population. This is an indication of the effectiveness of donor education and the use of the history questions in screening out high risk individuals from donation.
- The intent of each new generation of tests is to improve the detection of window period donations (“closing the window”) and decrease the rate of false positive screening tests.