Chapter 12

• It is the study of body fluids
▫ Blood
▫ Saliva
▫ Semen
▫ Urine

• 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

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

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

• 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

• Red blood cells (erythrocytes)
• White blood cells (leukocytes)
• Platelets (thrombocytes)
• Serum

• 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

• 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

• 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

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

• Is the liquid that separates from the blood when a clot is formed

• 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

• 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

• 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

• 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 bluegreen color
▫ Luminol test
 Reacts with blood to produce light

• 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

• 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

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

• 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

• Type A- 42%
• Type B- 12%
• Type AB- 3%
• Type O- 43%

• 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

• Rh+- 85%
• Rh- - 15%
• Of the Rh+ population, 85% are Caucasians,
94% are African Americans, and 99% are Asians

• 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

• 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

• 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