MLT GlobeBlood Banking: Donor selection & processing
75 Blood Banking MCQs on Donor selection & processing with answers and explanations.
What needle size is standard for whole-blood donor collection?
A wide 16–17 gauge needle allows rapid flow into the bag and minimizes shear damage to red cells. Higher gauge numbers are narrower needles.
Which infection is routinely screened for in donated blood because it is transmitted by transfusion?
Blood donations are screened for HBV, HCV, HIV and syphilis (and malaria where endemic). Tetanus, typhoid and tuberculosis are not routine transfusion-transmitted risks.
A prospective donor reveals a past confirmed positive anti-HIV result. What is the correct donor status?
A history of confirmed HIV, HCV or HBV infection leads to indefinite deferral, as the infection may persist and be transmitted by transfusion.
Which of these tests is a mandatory screen on every donated unit?
Syphilis screening is compulsory for all donations. CMV is tested only for selected recipients, hepatitis A is not routinely screened, and malaria testing depends on local epidemiology.
Which red cell group is traditionally regarded as the universal donor type?
O negative cells lack A, B and D antigens, so they can be given in emergencies before the patient's group is known.
A female donor's fingerstick haemoglobin is checked. What is the lowest value that allows her to donate under AABB criteria?
AABB sets 12.5 g/dL for women and 13.0 g/dL for men. Lower values protect the donor from post-donation anaemia.
Which test is NOT a universal mandatory screen for donated blood?
Every donated unit is screened for HIV, HBV (HBsAg) and HCV, plus syphilis. Schistosomiasis serology is not part of routine mandatory donor screening.
The minimum interval between two whole blood donations by the same donor is:
An interval of 8 weeks (56 days) lets the donor replace iron and red cells. Longer intervals apply after double red cell apheresis (16 weeks).
What is the minimum body weight for a donor to give a standard whole blood donation of about 500 mL?
A standard 450–500 mL collection is limited to donors weighing at least 50 kg (110 lb). Lighter donors need a reduced-volume collection with less anticoagulant.
A prospective whole blood donor has an oral temperature of 37.9 °C (100.2 °F). What is the correct action?
Donor temperature must be 37.5 °C (99.5 °F) or lower. A higher value may mean infection, so the donor is deferred; masking fever with an antipyretic is not acceptable.
Which recently given vaccine does NOT require donor deferral in a donor who feels well?
Toxoids and inactivated vaccines do not cause deferral in symptom-free donors. Live attenuated vaccines such as varicella, oral typhoid and yellow fever require a temporary deferral of 2–4 weeks.
What is the main benefit of adding nucleic acid testing (NAT) for HIV and HCV to antibody screening of donors?
NAT detects viral RNA days to weeks before antibody appears, so it closes much of the window period. It is not a confirmatory test for antibody results and does not detect bacteria.
A regular donor now tests positive for HIV. Tracing and notifying recipients of his earlier donations is called:
Lookback identifies prior components from a donor who later tests positive, so those units can be retrieved and recipients notified. Reentry is the process of requalifying a donor after a false-positive result.
During donation, a donor becomes pale, sweaty and dizzy with a slow pulse. What is the correct first action?
These are signs of a vasovagal reaction. The needle is removed, the donor lies flat with legs raised, and cold compresses are applied; the collection is not continued.
An autologous unit was not needed during surgery. What should be done with it?
Autologous donors do not meet all allogeneic donor criteria, so unused units are not crossed over for other patients. They are discarded after expiry or when no longer needed.
Which blood pressure is acceptable for an allogeneic whole blood donor?
Donors must have systolic pressure of 180 mmHg or less and diastolic pressure of 100 mmHg or less. Only 175/95 meets both limits.
A woman delivered a healthy baby 4 weeks ago and wants to donate whole blood. The correct decision is:
Donors are deferred during pregnancy and for 6 weeks after delivery, to protect maternal iron stores and health. Previous pregnancy does not cause permanent deferral.
What is the main purpose of the ISBT 128 labeling system?
ISBT 128 gives each donation a globally unique identification number and standard codes for product type, ABO/D and expiry. This supports traceability from donor to recipient.
Which skin preparation is widely recommended for the donor venipuncture site?
Chlorhexidine–alcohol reduces skin bacteria that can contaminate the unit, especially platelets. Povidone-iodine is an alternative for donors allergic to chlorhexidine. Alcohol alone is less effective.
Why is the collection bag gently mixed throughout whole blood donation?
Continuous mixing distributes the anticoagulant evenly so small clots do not form. Clots make the unit unusable and can block filters.