Immunohematology Lecture Notes

INTRODUCTION TO BLOOD BANKING

  • Blood banking is essential for transfusion medicine, providing safe blood for patients in need.
  • Advances in preservation techniques for red blood cells (RBCs) and platelets have improved transfusion safety, shelf life, and product availability.

HISTORY OF BLOOD TRANSFUSION

  • 1492: First recorded blood transfusion; all three recipients died.
  • 1889: Braxton Hicks recommended sodium phosphate as a blood preservative.
  • 1892: James Blundell performed the first successful transfusion on a post-partum hemorrhage patient.
  • 1902: Discovery of the 4th blood group by Von Descatello and Stunil.
  • 1913-1916: Significant advancements in transfusion techniques and anticoagulant use (e.g., sodium citrate).
  • 1941: Establishment of the first American Red Cross Blood Bank by Dr. Charles Drew.
  • 1979: Development of CPDA-1, improving RBC preservation.

BLOOD COMPONENTS AND SAFETY

  • Whole blood can be separated into components: packed RBCs, platelets, and plasma.
  • The high demand for blood transfusions (1 in 3 people) necessitates stringent donor screening and safety protocols.

BLOOD PRESSURE AND HEMOGLOBIN LEVELS

  • AABB Guidelines:
  • Systolic: ≤ 180 mmHg; Diastolic: ≤ 100 mmHg
  • Hemoglobin: Males ≥ 13.0 g/dL, Females ≥ 12.5 g/dL.

BLOOD DONATION STANDARDS

  • Minimum age in AABB: 16 years; Philippines: 10 years for new donors.
  • Donation frequency: 8 weeks (AABB) vs. 12 weeks (Philippines).
  • Temperature and pulse rate regulations are also in place.

DONOR SCREENING TESTING IN THE PHILIPPINES

  • Hepatitis B, C; HIV; Syphilis; Malaria screening through various tests (EIA, CLIA, PCR, etc.).

CIRCULATORY OVERLOAD PROCESS AND COMPONENT THERAPY

  • Component therapy allows targeted transfusions to prevent circulatory overload, a common issue with whole blood transfusions.

RBC BIOLOGY AND PRESERVATION

  • Key areas of RBC biology include membrane composition, hemoglobin function, and metabolism which affect their circulation lifespan of ~120 days.
  • RBC preservation maintains their viability and integrity during storage, typically at 1-6°C.

RBC ADDITIVE SOLUTIONS

  • Additive solutions improve RBC storage conditions by regulating hematocrit and preserving viability.

RBC FREEZING AND DEGLYCEROLIZATION

  • Freezing uses glycerol for storage, allowing RBCs to remain viable for up to 10 years.
  • Deglycerolization is necessary to return RBCs to normal osmolality post-thawing.

PLATELET STORAGE AND BACTERIAL CONTAMINATION

  • Platelets have a 5-day shelf life and are prone to bacterial contamination at room temperature.

CLINICAL USE OF PLATELETS

  • Indicated for treatment of bleeding due to thrombocytopenia; efficacy typically assessed through corrected count increment.

IMMUNOLOGY OVERVIEW

  • Immunity is the body's defense mechanism against pathogens, utilizing various immune cells and antibodies.
  • Blood bank testing focuses on identifying blood group antibodies and compatibility.

INNATE VS ADAPTIVE IMMUNITY

  • Innate immunity: non-specific, immediate defense mechanisms present from birth including physical barriers and phagocytosis.
  • Adaptive immunity: specific, slower response involving T and B lymphocytes that provide long-term protection through memory.

AUTOANTIBODIES AND ALLOANTIBODIES

  • Autoantibodies target the body's own antigens while alloantibodies are directed against antigens from genetically different individuals.

TRANSFUSION REACTIONS

  • Importance of understanding antigen-antibody interactions to prevent transfusion reactions, graft rejection, and hemolytic disease in newborns.

ANTIGLOBULIN TESTS

  • Direct and indirect tests for detecting antibodies or complement proteins bound to RBCs which are critical in blood transfusion and hemolytic conditions.

MONOCLONAL VS POLYCLONAL ANTIBODIES

  • Monoclonal antibodies are specific to one epitope, while polyclonal antibodies recognize multiple epitopes. Both types have distinct applications in laboratory testing and diagnosis.

FLOW CYTOMETRY

  • Utilizes fluorescently labeled antibodies to analyze cell populations, measure cell size and granularity.

TECHNIQUES IN BLOOD BANKING

  • Importance of various serological tests and molecular diagnostics in ensuring safe transfusions, including antibody screening and antigen typing.