Pathology Notes

Practice questions answers Blood transfusion I © Jun Wang, MD, PhD   1. C. Forward typing is to mix patient’s RBCs with anti-A and anti-B reagents. Agglutination to either or both reagents confirms the presence of these antigens on patient’s RBCs. Reverse typing is to mix patient’s serum with reagent A and B cells. Agglutination to either or both cells confirms the presence of anti-A or anti-B or both. This patient has agglutination with anti-B but not anti-A, confirmed RBCs have B-antigen, but not A-antigen. Reverse typing confirmed the presence of anti-A but not anti-B in his serum. This pattern is consistent with type B . Type A RBCs will have agglutination with anti-A reagent, but not anti-B reagent. Type A serum will agglutinate B cells but not A cells. Type AB RBCs will have agglutination with both anti-A and anti-B reagents, while type AB serum will not agglutinate A or B cells. Type O RBCs will not agglutinate with either anti-A or anti-B reagents, while its serum w...

Practice questions Blood transfusion I © Jun Wang, MD, PhD   1. Use this case for the next three questions . A 21-year-old man is brought to the emergency department after being involved in a motor vehicle accident. His blood pressure is 90/60 mmHg, and heart rate is 120 beats per minute. Physical examination reveals pale skin and mucosa and a 15 cm laceration on the left leg with active bleeding. His CBC reveals a hemoglobin of 8 g/dL. His white cell count, platelet count and coagulation panels are within normal ranges. Forward typing reveals agglutination with anti-B but not anti-A reagent. Reverse typing reveals agglutination with A cells, but not B cells. Antibody screening test is negative. What is his blood type? A. A B. AB   C. B D. Bombay E. O 2. A 21-year-old man is brought to the emergency department after being involved in a motor vehicle accident. His blood pressure is 90/60 mmHg, and heart rate is 120 beats per minute. Physical examination reveals pale skin ...

Transfusion associated circulatory overload (TACO) Updated: 07/28/2025 © Jun Wang, MD, PhD   General features Pulmonary edema secondary to excessive circulating volume Definition: New onset or exacerbation of three or more of the following within 12 hours of transfusion completed, without other explanation o    Respiratory distress o    Pulmonary edema on PE or image studies o    Elevated brain natriuretic protein (BNP) or N-terminal pro-hormone BNP o    Elevated central venous pressure, etc May be associated with transfusion of any blood product Risk factors include pre-existing cardiac or kidney dysfunction, age (children or elderly), anemia , and chronic pulmonary diseases Associated with rapid transfusion of large quantities of fluid Clinical presentations Acute onset Usually NO fever, urticaria or angioedema Presentation of congestive heart failure o    Dyspnea, coughing, orthopnea, bilateral rales, hypoxia ...

Transfusion related acute lung injury (TRALI) Updated: 07/28/2025 © Jun Wang, MD, PhD   General features Definition o    New acute lung injury within 6 hours of transfusion o    Lung injuries results in hypoxemia (PaO2≤300mmHg, or O2 saturation <90%) and bilateral infiltrates o    No other risk factors for pulmonary edema o    No pre-existing acute lung injury Most common cause of death associated with transfusion Commonly associated with platelets/plasma transfusion Clinical presentations Sudden onset, within up to 6 hours of initiation of transfusion Most cases occur within minutes after transfusion started Fever and chill Cyanosis Bilateral lung infiltrates on image studies Transient hypertension followed by hypotension Tachypnea, tachycardia, etc Key pathogenesis Most common: Donor antibodies against recipient neutrophils (anti-HLA or anti-neutrophil) Less common: Recipient antibodies against donor WBC Antibody-neutr...

Moderate allergic (anaphylactoid) and severe allergic (anaphylactic) transfusion reaction Updated: 07/28/2025 © Jun Wang, MD, PhD   General features Uncommon generally Commonly associated with IgA deficiency , haptoglobin deficiency, or other allergens presents in donor’s plasma (drugs, food components) Very uncommon to identify a specific allergen May cause hypotension, shock , etc   Clinical presentations Immediate onset Usually no fever Commonly airway obstruction beside urticaria (hives) , angioedema, etc Wheezing, chest tightness, dyspnea, etc Presentations of hypotension, shock , etc   Key pathogenesis IgE mediated (type I hypersensitivity) reaction toward plasma protein in donor units Activation of mast cells results in production of histamine and other cytokines Management Epinephrine Other supportive managements     Back to blood transfusion Back to contents    

Mild allergic transfusion reaction Updated: 07/28/2025 © Jun Wang, MD, PhD   General features AKA urticarial transfusion reaction Very common Clinical presentations Rapid onset, a few minutes after transfusion started Usually NO fever Usually localized urticaria (hives) May cause severe edema around eyes and lips (angioedema), laryngeal edema, or mild respiratory symptoms Key pathogenesis Usually IgE mediated (type I hypersensitivity) reaction toward plasma protein in donor units Activation of mast cells results in production of histamine and other cytokines Laboratory findings Non-specific Management Antihistamine: Benadryl (diphenhydramine) Consider washed RBCs (donor plasma removed) Transfusion may resume after hives cleared     Back to blood transfusion Back to contents

Febrile non-hemoltyic transfusion reaction Updated: 07/28/2025 © Jun Wang, MD, PhD   General features Unexplained fever of 1 ° C or 2 ° F or higher Commonly seen in oncology or transplant patients Incidence reduced due to leukocyte reduction of RBCs and platelets May be prevented by leukocyte reduction of donor RBC or platelets, especially before storage Clinical presentations Transient fever and chills Presents during or less than 2 hours after transfusion Key pathogenesis Pyrogens in donor’s units Most likely produced by leukocytes in donor units May be produced before or after transfusion Laboratory findings No evidence of hemolysis Management Antipyretics    Back to blood transfusion Back to contents