White Blood Cells Would Not Theoretically Increase After Transfusion
Among the listed options, white blood cells (WBCs) would not increase after transfusion, as modern blood products undergo prestorage leukoreduction, which removes >99.9% of donor leukocytes before transfusion. 1
Why Each Component Changes (or Doesn't) After Transfusion
White Blood Cells: No Increase Expected
- Prestorage leukoreduction has been universally implemented in modern blood banking, reducing febrile reactions by 35% and eliminating the transfer of significant numbers of donor WBCs 2
- The recipient's own WBC count reflects their endogenous production and clinical condition, not the transfused product 1
- Even before leukoreduction, transfused WBCs were rapidly cleared from circulation and did not meaningfully increase recipient WBC counts
Potassium: Increases
- Stored red blood cells accumulate extracellular potassium as the Na-K-ATPase pump fails during storage
- Massive transfusion can cause clinically significant hyperkalemia, particularly with older units
- This represents a well-recognized metabolic complication of transfusion
Bilirubin: Increases
- Transfused red blood cells undergo hemolysis (both intravascular in acute reactions and extravascular during normal senescence) 1
- Hemoglobin breakdown produces unconjugated bilirubin, which can be measured post-transfusion
- This is particularly evident in hemolytic transfusion reactions where bilirubin rises acutely 1
Platelets: Increase
- Platelet transfusions directly increase the recipient's platelet count—this is the therapeutic goal
- Each unit of apheresis platelets or pooled platelet concentrate raises the platelet count by approximately 30,000-50,000/μL in an average adult
- The increment is measurable within 1 hour post-transfusion
Risk of TRALI/TACO: Increases
- Both TRALI and TACO risks increase with each transfused unit 1
- TRALI occurs at a rate of 0.81 per 10,000 transfused blood components (8.1 per 100,000) 1
- TACO occurs in 1-8% of transfused patients depending on the population studied, with rates of 2-3 per 100 transfused RBC units in ICU patients 1
- TACO is now the most common cause of transfusion-related mortality and major morbidity 3
- Fresh frozen plasma and platelet concentrates are most frequently implicated in TRALI 3, 4
Clinical Implications
The correct answer is white blood cells, as leukoreduction has effectively eliminated the transfer of donor WBCs in modern transfusion practice 2. All other listed parameters demonstrably increase: potassium from RBC storage lesion, bilirubin from hemolysis, platelets from direct infusion, and TRALI/TACO risk from cumulative transfusion exposure 1, 3.
Key Monitoring Points
- Monitor potassium levels during massive transfusion protocols
- Expect mild bilirubin elevation post-transfusion from normal RBC turnover 1
- Assess for TACO/TRALI within 6 hours of transfusion by monitoring respiratory status, oxygen saturation, and vital signs 3, 5
- Platelet count increments should be checked 1 hour and 24 hours post-transfusion to assess response