MLS 2551 Unit 5: Donor Selection, Testing & RBC Compatibility

What is the first step in creating a usable blood component?

A protected donor and a controlled collection process.

What factors determine the release decision of a blood donation?

The whole donation record, including eligibility criteria and testing results.

What must remain traceable for a blood component to be available?

The donation identifier through testing and component preparation.

What does donor eligibility protect?

Both the donor's health and the recipient's safety.

What should be included in the donor history assessment?

Identity verification, illness history, relevant exposures, travel, procedures, and medications.

What are the ordinary physical criteria for blood donation?

Specified donor category, hemoglobin (Hb) or hematocrit (Hct) levels, age, and consent.

What is the minimum hemoglobin level for male allogeneic donors?

13.0 g/dL.

What is the recovery interval after a single-unit whole blood donation?

At least 8 weeks.

What distinguishes whole blood collection from apheresis?

Whole blood collection removes blood into a collection system, while apheresis separates components and returns others.

What controls are necessary to preserve blood component quality?

Traceability of donor, bag, and sample, validated skin preparation, and correct blood-to-anticoagulant ratios.

What are common donor reactions during blood donation?

Pallor, sweating, nausea, faintness, and perioral tingling.

What is the significance of a passing hemoglobin result?

It supports donor eligibility but does not complete the assessment.

What does donor testing establish?

Component identity, including ABO and RhD classification.

What is the purpose of nucleic acid testing (NAT) in blood donation?

To detect an agent's genetic material, improving infection detection.

Why is a history assessment important in donor screening?

To identify risks that laboratory testing alone may miss.

What is the window period in blood donation?

The interval in which infection may be present before the relevant test becomes reactive.

What happens if a donor sample demonstrates weak D?

The donation is labeled as Rh positive.

What is the minimum donation interval for double-RBC apheresis?

At least 16 weeks.

What is the role of the donation identifier D-1030?

It links to the collection, samples, and resulting components.

What is the significance of maintaining the correct blood-to-anticoagulant relationship?

It ensures the quality and safety of the collected blood component.

What should be documented during the blood collection process?

Collection details and any later donor information.

What are the implications of apheresis for donor criteria?

It determines citrate exposure and collection controls.

What is the impact of iron stores on hemoglobin eligibility?

Hemoglobin eligibility does not establish normal iron stores.

What is the importance of informed consent in blood donation?

It ensures donors understand the process, risks, and can withdraw if desired.

What is the primary goal of donor screening assays?

To ensure the safety and suitability of blood donations for transfusion.

How does the current screening matrix function?

It uses specified assays to detect various agents in blood donations.

What screening strategy is used for West Nile Virus (WNV) in donors?

Routine donor NAT, responding to local activity.

What is the testing strategy for Chagas disease in donors?

One-time donor antibody testing with verified records.

What is the recommended testing for Babesia in donors?

Regional year-round NAT or an eligible approved pathogen-reduction pathway.

What is the risk associated with room-temperature platelets?

Bacterial growth if contamination occurs.

What methods reduce the risk of bacterial entry in platelet donation?

Donor assessment, skin preparation, and diversion.

What should be done with a donation that has a reactive infectious screen?

Containment and quarantine while further testing is conducted.

What does a nonreactive result in infectious screening indicate?

The case can proceed with manufacturing, storage, labeling, and final inspection.

What is the purpose of component preparation in blood donation?

To separate useful fractions such as RBC, plasma, and platelets.

How does centrifugation contribute to blood component preparation?

It separates fractions through a validated process.

What is the effect of an intact closed pathway on blood component storage?

It limits environmental entry and preserves the component's expiration date.

What are the three metabolic pathways that explain RBC preservation?

Glycolysis, pentose-phosphate pathway, and 2,3-DPG regulation.

What happens to ATP and 2,3-DPG levels during cold storage of RBCs?

They generally decrease.

What increases in the supernatant during RBC storage?

Extracellular potassium and lactate increase, while pH decreases.

How does lower 2,3-DPG affect hemoglobin's oxygen affinity?

It shifts the oxygen dissociation curve left, increasing oxygen retention.

What role does citrate play in blood preservation?

It binds calcium and prevents coagulation.

What is the purpose of dextrose in blood preservation?

It supplies metabolic substrate.

What is the typical storage temperature range for conventional liquid RBCs?

1-6°C.

What is the common collection-date limit for conventional additive-solution RBCs?

42 days.

What protects RBCs during the freezing process?

Glycerol.

What is controlled deglycerolization?

The process of removing glycerol from RBCs before transfusion.

What is the significance of validated testing in platelet safety?

It controls remaining risk during the storage period.

What happens to membrane integrity during RBC storage?

Membrane changes and hemolysis can accumulate.

What is the impact of open-system processing on blood component storage?

It introduces a shorter expiration limit.

What is the importance of donor history and testing in blood donation?

They remain complementary for ensuring safety and efficacy.

What does the term 'storage lesion' refer to?

The changes in RBC metabolism and supernatant composition during storage.

What is the function of phosphate in blood preservation?

It contributes buffering and metabolic support.

What is the role of 2,3-DPG in stored RBCs?

It helps regulate hemoglobin's oxygen affinity.

What is the purpose of apheresis in blood donation?

It provides a different collection route to selected components.

How long can ordinary frozen blood components be stored?

Up to 10 years at −65°C or colder.

What is the purpose of rejuvenation in blood processing?

To restore or increase ATP and 2,3-DPG in red blood cells.

What must be done after the rejuvenation process?

The rejuvenating solution must be removed before transfusion.

What happens to stored platelets over time?

They continue metabolism, may become activated, and can accumulate lactate.

What is the storage temperature for conventional platelets?

20-24°C with continuous gentle agitation.

What does PAS stand for in blood component processing?

Platelet Additive Solution.

What is the role of pathogen reduction in blood components?

To act on susceptible infectious agents through an approved process.

What does FFP stand for?

Fresh Frozen Plasma.

What is the significance of prompt plasma separation?

It preserves coagulation proteins in the plasma.

What does product QC check in blood components?

It checks component specifications like platelet yield, pH, and appearance.

How is platelet yield calculated?

Example: 1.2×10⁶ platelets/µL × 250 mL × 1,000 µL/mL = 3.0×10¹¹ platelets.

What is the minimum pH for end-storage of platelets?

At least 6.2 at the storage temperature.

What does the label of a blood component indicate?

It connects the product to its handling requirements and processing attributes.

What happens if a component undergoes open-system washing?

The earlier expiration controls after open processing.

What is required for a completed suitability review of blood inventory?

Eligibility, collection records, testing, and component status must be acceptable.

What must be confirmed before marking a blood component as available?

Satisfactory eligibility, collection, testing, and preparation records.

What is the importance of donor assessment in blood processing?

It protects both the donor and recipient from infectious risks.

What does the term 'component integrity' refer to?

The requirement that all findings remain satisfactory after inspection.

What is the purpose of the linked source and its date in blood processing?

To verify rules or product pathways when needed.

What does the end-storage QC sample measure?

It measures the pH of the blood component.

What is the significance of the cryoprecipitate-rich fraction?

It is obtained from cold thawing of source plasma.

What is the consequence of a QC failure in blood components?

It requires investigation and corrective action.

What does the term 'approved procedure' refer to in blood processing?

The standardized methods for processing, storage, and labeling of blood components.

What is the role of bacterial control in platelet storage?

To prevent contamination and maintain the quality of stored platelets.

What does the term 'satisfactory component' mean?

A component that meets its defined quality and processing requirements.

What is the importance of the storage requirement on a blood component label?

It indicates how the component should be stored to maintain its quality.

Why is prior antibody history important in transfusion?

Prior antibodies can persist even if current screens are negative, affecting donor selection.

What must a recipient's anti-A and/or anti-B antibodies not encounter?

Incompatible donor RBC antigens.

What does safe release of blood depend on?

Correct patient identification, reliable specimen, pertinent history, appropriate testing, and the right donor unit.

What is the first step when a request for RBC units is received?

Identify the information the laboratory needs before choosing a crossmatch.

What is the significance of antibody identification in transfusion practice?

It guides donor antigen requirements and compatibility investigations.

What is the full pretransfusion safety chain?

Request → Identify → History → ABO/D + screen → Select RBCs → Crossmatch → Issue.

What must be confirmed before accepting a specimen?

Identity, component, amount, urgency, relevant history, and specific product needs.

What is required for patient identification before specimen collection?

Use two unique identifiers and reconcile them with the wristband and authorized request.

What does traceability in the transfusion process ensure?

That the patient, tube, request, and unit are all linked correctly.

What should be done if there is a mismatch between patient wristband and specimen label?

Investigate and potentially recollect under laboratory SOP.

What factors contribute to an acceptable specimen?

Identity, integrity, timing, and adequate volume without contamination or clotting issues.

How does recent antigen exposure affect antibody screening?

It may lead to the development of new antibodies, necessitating reassessment.

What is the U.S. three-day specimen rule?

A fresh sample is required if a patient has had a transfusion or pregnancy within the last three months.

What role does technology play in specimen identification?

It supports but cannot replace the need for human verification of identity.

What should be done if a specimen has a different medical record number than the wristband?

Investigate the discrepancy and potentially recollect the specimen.

What is the first safeguard in the transfusion process?

Establishing the identity of the patient before any results can be interpreted.

How is a current patient result interpreted?

Alongside the retained historical record, including prior transfusions and antibody screens.

What must be reviewed in the patient's historical record?

Prior ABO/D results, clinically significant antibodies, prior compatibility events, transfusions, and pregnancies.

What does a negative screen indicate in pretransfusion testing?

A negative screen does not mean the patient has never had an antibody; previously detected alloantibodies may fall below routine detection.

What is the significance of historical anti-Jkᵇ in a patient's workup?

The initial negative screen does not close the patient's workup; anti-Jkᵇ remains clinically significant and affects RBC selection.