In the United States today, the most frequent infectious complication of transfusion is:

Bacterial sepsis, mostly from platelets

HIV infection despite NAT testing

Hepatitis B infection from plasma

Hepatitis C infection from red cells

During a West Nile virus outbreak, blood centers switch from minipool to individual-donation NAT. Why?

Low-level viremia can be missed when samples are pooled

Individual testing detects antibody instead of RNA

Minipool testing cannot detect any flavivirus

Pooling causes too many false-positive results

Babesia microti is transmitted by transfusion mainly through:

Red cell units, as the parasite lives in red cells

Plasma units, as it is a plasma-borne virus

Platelet units only, as it binds to platelets

Cryoprecipitate, as it is concentrated in cold

Adverse effects: transfusion-transmitted diseases

7 ASCP MLS practice questions on Adverse effects: transfusion-transmitted diseases, part of Blood Banking. The first 7 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Easy
In the United States today, the most frequent infectious complication of transfusion is:
1. AHIV infection despite NAT testing
2. BHepatitis B infection from plasma
3. CHepatitis C infection from red cells
4. DBacterial sepsis, mostly from platelets
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Answer: D · Bacterial sepsis, mostly from platelets
Nucleic acid testing has made viral transmission of HIV, hepatitis C and hepatitis B very rare. Bacterial contamination now causes more transfusion infections than any virus. Platelets carry the highest risk because they are stored at room temperature, where bacteria multiply. Skin disinfection, diversion pouches, bacterial testing and pathogen reduction lower the risk.
- A: HIV transmission is now extremely rare because of donor screening and NAT.
- B: Hepatitis B transmission is rare because of HBsAg, anti-HBc and NAT testing.
- C: Hepatitis C transmission is now extremely rare because of NAT.
Question 2 · Medium
During a West Nile virus outbreak, blood centers switch from minipool to individual-donation NAT. Why?
1. AIndividual testing detects antibody instead of RNA
2. BMinipool testing cannot detect any flavivirus
3. CLow-level viremia can be missed when samples are pooled
4. DPooling causes too many false-positive results
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Answer: C · Low-level viremia can be missed when samples are pooled
Minipool NAT dilutes each donor sample, so donations with low amounts of virus can test negative. When cases rise in an area, centers test each donation separately to catch these low-level infections. They switch back to minipools when local activity falls. West Nile virus testing is required for all US donations.
- A: Both methods detect viral RNA, not antibody.
- B: Minipool NAT detects West Nile virus at higher viral loads.
- D: Pooling lowers sensitivity; false positives are not the reason.
Question 3 · Medium
During transfusion of a red cell unit stored for 35 days, a patient develops fever, rigors and hypotension. A Gram stain of the unit shows gram-negative rods. Which organism is classically linked to contaminated refrigerated red cells?
1. ACutibacterium acnes
2. BBacillus cereus
3. CYersinia enterocolitica
4. DStaphylococcus epidermidis
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Answer: C · Yersinia enterocolitica
Yersinia enterocolitica can grow at 1 to 6 °C and thrives on the iron released in stored red cells. It comes from donors with a mild or silent intestinal infection, and older units carry more organisms and endotoxin. The transfusion is stopped, and the unit and patient are cultured. Other cold-tolerant gram-negative rods, such as Serratia and Pseudomonas fluorescens, are also reported.
- A: Cutibacterium acnes is a gram-positive skin organism, mainly found in platelets.
- B: Bacillus cereus is a gram-positive rod and is not the classic red cell contaminant.
- D: Staphylococcus epidermidis is a gram-positive skin organism, typical of contaminated platelets.
Question 4 · Medium
Babesia microti is transmitted by transfusion mainly through:
1. APlasma units, as it is a plasma-borne virus
2. BRed cell units, as the parasite lives in red cells
3. CPlatelet units only, as it binds to platelets
4. DCryoprecipitate, as it is concentrated in cold
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Answer: B · Red cell units, as the parasite lives in red cells
Babesia microti is a tick-borne parasite that infects red cells and survives refrigerated storage. Donors are often unaware of infection, and recipients who are elderly, asplenic or immunocompromised can become severely ill. US blood centers in high-risk states test donations for Babesia by NAT, or use pathogen reduction where approved. Most cases come from the Northeast and upper Midwest.
- A: Babesia is a protozoan parasite in red cells, not a plasma-borne virus.
- C: Babesia infects red cells; red cell units are the main source.
- D: Cryoprecipitate contains very few red cells and is not the main source.
Question 5 · Hard
A hospital uses amotosalen/UVA pathogen-reduced platelets. Which practice can it stop for these units?
1. AVisual inspection before issue
2. BBedside patient identification
3. CABO compatibility checks
4. DIrradiation to prevent TA-GVHD
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Answer: D · Irradiation to prevent TA-GVHD
Amotosalen binds to DNA and RNA and, with UVA light, cross-links them so that bacteria, many viruses and donor lymphocytes cannot replicate. FDA accepts these platelets in place of irradiation, CMV-seronegative units and further bacterial testing. The method does not inactivate every agent, for example some bacterial spores and certain nonenveloped viruses. ABO selection, inspection and patient identification still apply.
- A: Every unit is still inspected before issue.
- B: Patient identification is required for every transfusion.
- C: ABO compatibility still matters for pathogen-reduced platelets.
Question 6 · Hard
A platelet unit had a negative bacterial culture from a sample taken 24 hours after collection, yet caused a septic reaction on day 5 of storage. The best explanation is:
1. AToo few bacteria were present when the early sample was taken
2. BPlatelet units cause sepsis only through endotoxin in the bag
3. CCultures detect only gram-negative bacteria
4. DThe reaction must have come from the patient's own bacteremia
Answer and explanation in LearnFree account
Question 7 · Hard
Twenty minutes into a day-5 apheresis platelet unit, a 39-year-old woman with lymphoma develops rigors, a temperature rise from 36.9 to 39.7 °C and a blood pressure of 78/40 mm Hg. The transfusion is stopped and blood cultures are drawn from her. The clerical check is correct, the post-transfusion plasma is not hemolyzed and the DAT is negative. A Gram stain of the residual unit shows gram-positive cocci in clusters. The unit was one of two split products from a single collection; the other went to another hospital yesterday. What should the blood bank do next?
1. ANotify the supplier to quarantine the split unit
2. BWait for culture identification before reporting
3. CClassify it as a febrile nonhemolytic reaction
4. DRepeat the workup with an eluate and a panel
Answer and explanation in LearnFree account

Adverse effects: transfusion-transmitted diseases

In the United States today, the most frequent infectious complication of transfusion is:

During a West Nile virus outbreak, blood centers switch from minipool to individual-donation NAT. Why?

During transfusion of a red cell unit stored for 35 days, a patient develops fever, rigors and hypotension. A Gram stain of the unit shows gram-negative rods. Which organism is classically linked to contaminated refrigerated red cells?

Babesia microti is transmitted by transfusion mainly through:

A hospital uses amotosalen/UVA pathogen-reduced platelets. Which practice can it stop for these units?

A platelet unit had a negative bacterial culture from a sample taken 24 hours after collection, yet caused a septic reaction on day 5 of storage. The best explanation is: