What is the approximate incidence range of bacterial contamination in a unit of apheresis platelets?

• A. 1/10,000
• B. 1/1000 ~ 1/4000
• C. 1/50
• D. 1/2

Answer: (B)

The key idea is that bacterial contamination in apheresis platelets is relatively uncommon but not negligible. Platelets are stored at room temperature, which supports bacterial growth, so contamination rates are higher than for some other components, but still very low overall. Surveillance data and studies typically place the contamination rate around 1 in 1000 to 1 in 4000 units, which matches the range 1/1000 to 1/4000. This is why the best answer is the range that spans roughly 0.1% to 0.025%.

Why the other options don’t fit: 1 in 50 (about 2%) is far higher than observed rates and would imply frequent issues, which isn’t supported by data. 1 in 10,000 is lower than commonly reported rates. 1 in 2 would mean contamination in half of units, which is not realistic in routine practice.