1. Serology Chapter 12

2. Serology It is the study of body fluids ▫Blood ▫Saliva ▫Semen ▫Urine

3. Functions of Blood Blood has 3 main functions ▫Transportation  Oxygen, carbon dioxide, wastes, nutrients, heat, & hormones ▫Regulation  Ph, body temperature, water content ▫Protection  From disease & loss of blood

4. Characteristics of Blood Thicker than H 2 O and flows more slowly 100.4 F temp Ph of 7.4 8% of body weight Blood volume ▫Male- 5-6 liters ▫Female- 4-5 liters

5. Components of Blood Blood consists of ▫55% plasma ▫45% cells  99% RBC (red blood cells)  <1% WBC (white blood cells) and platelets

7. Plasma 90% H 2 O 7% plasma proteins ▫Albumin- maintain blood osmotic pressure ▫Globulin- form antigen- antibody complexes ▫Fibrinogen- for clotting 3% other substances ▫Electrolytes, nutrients, hormones, gases, waste products

8. Formed Elements of Blood Red blood cells (erythrocytes) White blood cells (leukocytes) Platelets (thrombocytes) Serum

9. Formation of Blood Cells Blood cells need to be replaced continuously ▫Die within hours, days, or weeks ▫Process is called hematopoiesis In embryo, occurs in yolk sac, liver, spleen, thymus, lymph nodes, & red bone marrow In adult- occurs in red bone marrow of sternum, ribs, skull, & pelvis

10. Red Blood Cells (RBC) Contains hemoglobin (carries oxygen) ▫Gives it its red color ▫Makes up 1/3 of cell ’ s weight Is biconcave ▫Increased sa:vol ▫Flexible for narrow passages ▫No nucleus or organelles (no cell division) In adult ▫Male- 5.4 million RBC/gttp (drop) ▫Female- 4.8 million RBC/gttp

11. White Blood Cells (WBC) Are leukocytes Have a nucleus and no hemoglobin Classified as granular or agranular based on presence of granules in the cytoplasm ▫Granulocytes- neutrophils, eosinophils, basophils ▫Agranulocytes- monocytes, lymphocytes

12. Platelets Disc shaped No nucleus present Normal count ▫150000- 400000 gttp/blood Other blood cell counts ▫5 million RBC ▫5-10000 WBC

13. Serum Is the liquid that separates from the blood when a clot is formed

14. Immunoassay Techniques Are available for detecting drugs through antigen-antibody reactions 2 types of processes ▫EMIT (enzyme multiplied immunoassay technique)  Antibodies that bind to a specific drug are added to a subject ’ s urine ▫RIA (radioimmunoassay)  Uses drugs labeled with radioactive tags

15. Antigen-Antibody Reactions When an animal is injected with an antigen, its body will produce a series of different antibodies, all of which are designed to attack some particular site on the antigen of interest ▫Called polyclonal antibodies Antibodies designed to combine with a single antigen site can be manufactured ▫Called monoclonal antibodies

16. Forensics of Blood The criminalist must be prepared to answer the following questions when examining dried blood ▫Is it blood? ▫From what species did the blood originate? ▫If the blood is of human origin, how closely can it be associated to a particular individual Detection of blood is best made by means of a preliminary color test

17. Presumptive Tests for Blood Determination 3 tests ▫Kastle-Meyer color test  Is a mixture of phenolphthalein and hydrogen peroxide  Hemoglobin of blood will cause a deep pink color if blood is present ▫Hematest tablet  Reacts with the heme group in blood causing a blue- green color ▫Luminol test  Reacts with blood to produce light

18. Human vs. Animal Blood Once the stain has been characterized as blood, the precipitin test will determine whether the stain is of human or animal origin ▫Uses antisera normally derived from rabbits that have injected with the blood of a known animal to determine the species origin of a questioned bloodstain Once the bloodstain has been determined to be of human origin, the blood is typed

19. The Discovery of Blood Types Before Landsteiner ’ s discovery, countless people died from blood transfusions ▫There was an assumption back then that everybody had the same blood In 1900, Landsteiner proved that there are four different types of blood based on the presence or absence of specific antigens on the surface of RBC ’ s ▫Known as ABO blood group In 1940, he discovered the Rh factor

20. Blood Types RBC surfaces are marked by genetically determined glycoproteins & glycolipids ▫Agglutinogens or antigens ▫Distinguishes at least 24 different blood types  Most common= ABO & RH

21. ABO Blood Groups Based on 2 glycolipid antigens (A & B) found on the surfaces of RBC ▫Antigen A only= type A blood ▫Antigen B only= type B blood ▫Both antigens= type AB blood ▫No antigens= type O blood Plasma contains antibodies or agglutinins to the A or B antigens not found in your blood ▫Anti- A antibody reacts with antigen A ▫Anti-B antibody reacts with antigen B

23. Breakdown of ABO Blood Types Type A- 42% Type B- 12% Type AB- 3% Type O- 43%

24. Rh Factor Antigen was discovered in rhesus monkey ▫Called Rh antigen or D antigen People with Rh agglutogens on RBC surface are Rh+ (normal plasma contains no anti-Rh antibodies) Antibodies develop only in Rh- blood type & only with exposure to the antigen

25. Breakdown of Rh Blood Type Rh+- 85% Rh- - 15% Of the Rh+ population, 85% are Caucasians, 94% are African Americans, and 99% are Asians

26. Universal Donors and Recipients People with type AB blood are called universal recipients ▫No antibodies present ▫Can receive blood from anybody People with type O blood are called universal donors ▫No antigens present ▫Can donate blood to anybody

27. Typing and Cross Matching of Blood Mixing of incompatible blood causes agglutination (visible clumping) ▫Formation of antigen- antibody complex that sticks cells together ▫Not the same as blood clotting Typing involves testing blood with known antisera that contains antibodies A, B, or Rh+ Cross matching is to test by mixing donor cells with recipient ’ s serum Screening is to test recipient ’ s serum against known RBC ’ s having known antigens

28. ABO vs. DNA Prior to the advent of DNA typing, bloodstains were linked to a source by ABO bloodtyping DNA analysis has allowed forensic scientists to associated blood and semen stains to a single individual