Forensic Serology Lecture Notes (copy)

Serology Overview

  • Study of physiological (bodily) fluids.

Forensic Blood Evidence Steps

  • Recognition: Identify where blood is located.

  • Search: Locate evidence effectively.

  • Collect: Gather blood samples.

  • Package: Properly store the samples.

  • Identification: Determine the type of blood.

  • Individualization: Ascertain whose blood it is.

  • Reconstruction: Analyze how blood arrived at the scene.

History of Blood Research

  • 1901: Karl Landsteiner discovered blood types A, B, and O.

  • 1902: Alfred von Decastello contributed further, discovering AB.

  • 1937: Landsteiner and Alex Wiener identified Rh Protein.

  • 1922: Percy Oliver established a blood donor service. 

Composition of Blood

  • Blood: Tissue that is both solid and liquid.

  • Total volume in adults: Approximately 4–6 liters.

Blood Components

  • Composition: 55% plasma, 45% red blood cells, <1% white blood cells and platelets.

  • Red Blood Cells (RBCs): Transport oxygen; lifespan ~120 days.

  • Plasma: The liquid component of blood, constituting about 55% of its volume, it carries salts and various proteins throughout the body. (90% water)

  • White Blood Cells (WBCs): Fight infection; lifespan ~10 days.

  • Platelets: Help with clotting; lifespan ~5 days.

Blood Structure

  • Red Blood Cells: Approximately 5 million in a drop of blood, only have a nucleus when young, made in bone marrow.

  • White Blood Cells: Approximately 8000 in a drop of blood; produced in bone marrow and other organs.

  • Platelets: Approximately 250,000 per drop.

Blood Antigens and Antibodies

  • Antigens: Found on RBC surface (A, B).

  • Antibodies: Found in plasma (Anti-A, Anti-B).

  • Antibodies are bivalent with 2 reactive sites.

ABO Blood System

  • Agglutination: Clumping of red blood cells due to antibody-antigen interactions.

The Blood Cells

  • Red blood cells: erythrocytes. 

  • White blood cells: leukocytes

  • Platelets: thrombocytes