Serology (Chapter 6)

Blood Properties Accounts for about 8 % of total body weight. 5 to 6 liters of blood for males. 4 to 5 liters of blood for females. A 40 % blood loss, internally or/and externally, is required to produce irreversible shock (death). A blood loss of 1.5 liters, internally or externally, is required to cause incapacitation.

Did someone die?

What is Blood? A complex mixture of cells, enzymes, proteins & inorganic substances Fluid portion of blood is called the plasma (55% of blood content) primarily water Cells: Red cells (erythrocytes) White cells (leukocytes) Platelets (thrombocytes)

Plasma Plasma is a clear, yellowish fluid (the color of straw). Plasma is 90-percent water. The rest is protein. Includes: fibrinogen, salts, proteins, glycoproteins, carbohydrates, antibodies, hormones (e.g., insulin, testosterone, estrogen, adrenaline or epinephrine, etc.), albumin, and dissolved gases. The most common protein in our plasma is albumin, which is responsible for maintaining a proper fluid balance between our tissues and the rest of our bodies.

Red Blood Cells There are several things about RBCs that make them unusual: A RBC has a strange biconcave shape A RBC has no nucleus. A RBC can change shape to an amazing extent, without breaking, as it squeezes single file through the capillaries. A RBC contains hemoglobin, a molecule specially designed to hold oxygen

Blood Chemistry Hemoglobin (basic unit in red blood cells) is a protein containing heme groups.

Red Blood Cells Transport oxygen from the lungs to the body tissues Transport carbon dioxide from the tissues to the lungs Red cells possess chemical structures on their surfaces called antigens or agglutinogens impart blood type characteristics

Red Blood Cells Erythrocytes (RBCs) most abundant Avg 5,000,000 RBCs per cubic microliter (mm3). RBCs account for 40 to 45% of the blood. RBC #s measured with a hematocrit. The ratio of cells in normal blood is 600 RBCs for each white blood cell and 40 platelets.

Blood smear Normal Abnormal

White Blood Cells and Platelets White blood cells (leukocytes), are a part of the immune system and fight infection. WBCs : normally 4,000 to 10,000 (average 7,000) WBCs per microliter (mm3) of blood. Increases could be a sign of an infection Platelets (thrombocytes) help blood to clot by forming a platelet plug, blood clots (through coagulation factors), or other blood clotting mechanisms. There are approximately 150,000 to 400,000 platelets in each microliter of blood (average is 250,000).

Blood Clotting All this happens to clot blood! Blood Clot Formation (blood cells, platelets, fibrin clot) All this happens to clot blood!

Circulatory Pathway of Blood

Circulatory Pathway of Blood

The Liver and Blood

Kidneys “clean” waste products from blood stream (especially urea - a product of protein metabolism)

Forensic Blood Analysis Blood ID (“Is it blood”?) Blood origin (human or other source?) Blood Type? Blood Spatter Analysis. Where was victim in scene? Where was perp? What type of trauma? And more later…

Is it blood? Presumptive Test Confirmatory Test An analysis that suggests blood could be present Fast and relatively sensitive Confirmatory Test An experiment that can indicate the presence of blood with a high degree of certainty

Is it blood? Hemoglobin has peroxidase-like activity (enzymes that accelerate oxidation of organic compounds). Benzidine Color Test - previously used but dropped due to carcinogenic reagents. Kastle-Meyer Test - uses phenolphthalein. Blood+ phenolphthalein + H2O2 yields a deep pink color. Can give false positives (horseradish, some vegetables, potatoes, etc.)

Is it blood? Detects Peroxidase activity in blood One drop of water on stick Rub on stain After 60sec get color change to green

Is it blood? Luminol Test. Reaction of luminol w/ blood produces a complex which can be seen by luminescence. Very sensitive - up to a 3,000,000 dilution of blood can be seen. Detects unseen samples and patterns. Does not interfere with later DNA testing.

Is it human blood? Blood origin (human or other source). Precipitin Test - When animals are injected w/ human blood they form antibodies to the human blood. Can isolate human antiserum (antibodies to human blood). Human antiserum will react with human blood. Antiserum can (has) been made similarly for many other animals. Works on old (dried for many years) and small samples of blood.

If human, what type? Blood Type. ABO and Rh testing. Additional blood groupings Enzyme presence (many possible enzymes can be determined that are genetically controlled). An Immunoassay

Blood Types Karl Landsteiner, 1900 Noted that when blood from different people is mixed it sometimes forms precipitate - deadly if mixed in body. Explored why. Blundell's blood transfusion apparatus, 19th century

Blood Types B A B A Rh + Rh -

Blood Types-Transfusions AB Person has Anti-A and Anti-B Plasma Antibodies Person has Anti-B Plasma Antibodies Person has Anti-A Plasma Antibodies Person has no plasma antibodies against blood antigens Universal Receiver Universal Donor (43%) (42%) (12%) (3%)

Blood Type Genetics Three types (alleles) of blood type gene A, B, O Each individual inherits one blood type gene from their mother & one from their father 6 possible combinations (genotypes) AA, BB, OO, AB, AO, and BO Genotype determines blood type

Relative Frequency of Blood Types in Human Populations

Blood Types - Paternity And the Father Is: A B AB O If the Mom is: A or O A, B, AB, or O A, B, or AB The Child Must Be: A, B, AB or O B or O A, B or AB A or B iAiA or iAi - Both genotypes produce the A protein (type A). iBiB or iBi - Both genotypes produce the B protein (type B). iAiB - This genotype produces the A and B protein (type AB). ii - This genotype produces no protein (type O).

We use antibodies in Immunoassays to determine blood types

What is Serology? What is Immunology? A term which describes laboratory tests which employ a specific antigen and serum antibody reactions What is Immunology? A term which deals with all aspects of the immune system – specific to the interactions between antibodies and antigens

Immuno Assay Y Y Y Y Anti-A A A A Antibody-Antigen Interaction= Agglutination (Clumping of cells) A

Immuno-Assay

Blood type determination from nonblood fluids 80% of people are Secretors Find blood antigens (ie. A, B, Rh) in saliva, semen, vaginal fluids, gastric juice

Blood Spatter Analysis Bloodstain Pattern Analysis: the examination of the shapes, locations, and distribution patterns of bloodstains, in order to provide an interpretation of the physical events which gave rise to their origin. Bloodstain Pattern Analysis can be used to: Confirm or refute assumptions concerning events and their sequence: Position of victim (standing, sitting, lying). Evidence of a struggle. (blood smears, blood trails) Confirm or refute statements made by principals in the case: Are stain patterns on a suspects clothing consistent with his reported actions? Are stain patterns on a victim or at a scene consistent with accounts given by witnesses or the suspect?

Bloodstains Passive Projected Transfer

Passive Bloodstains 1) Passive Bloodstains are drops created or formed solely by the force of gravity (low speed). The force of impact is 5 ft/sec or less, size of the droplets between four and eight millimeters (0.16 to 0.31 inches) Can be subdivided into drops, drip patterns, pools, and clots.

Drops

Trails

Pools

Dripping Blood Blood trickles downwards Blood drop grows until Wt (G) > S.T. Single drop breaks free (teardrop shape) Surface tension pulls in vertically And horizontally Shape settles into sphere (0.05 ml) Does not break up until impact

. . . Drop size Standard drop size 50ul (0.05ml) Rapid bleeding gives slightly larger drop Shaking/movement casts off smaller drops . . .

Target Surface Type Smooth Linoleum Concrete Bloodstains can occur on a variety of surfaces including clothing, carpeting, walls, etc. The type of surface the blood strikes affects the nature of the observed splatter pattern. Hard smooth surface (e.g., glass): little distortion around the edges of the droplet. Irregular linoleum flooring: often show distortion (scalloping) around the edge of the droplets. Wood or concrete: distorted to a larger extent (e.g., spines and secondary splatter). Smooth Linoleum Concrete

Blood Spatter-Surface Texture Hard Surface 900 Drop The more soft, porous surface, the more uneven edges of drop

Impact Angle and Spatter

Drip Pattern Free-falling drops dripping into wet blood Large irregular central stain Small round & oval satellite stains . . . . . . . . . . .

Drip 1: Blood dripping into itself from height of 1 m (8 drops)

Transfer Bloodstains 2) A transfer bloodstain is created when a wet, bloody surface comes in contact with another surface. Ex. Contact bleeding, Swipe, Wipe, and Smudge.

Contact Bleeding

Swipe Bloody object touches a surface

Wipes Someone cleaning up a bloodstain… Maybe use towel or sponge etc. Can see direction of wipe

Smudge (Smear) Cleaning action of bloodstain but can’t determine a single direction of movement for whole stain

Projected Bloodstains 3) created when a blood source is subjected to an action greater than the force of gravity.  size, shape, and number of resulting stains will depend on the amount of force utilized to strike the blood source.

Projected Bloodstains – Impact Medium Velocity - Force of 5 to 25 feet/sec. Stain size 1 to 4 mm. Beatings, Blunt Object Trauma High Velocity - Force of 100 feet/sec. and greater. Stain size 1 mm and smaller (Mist like appearance). Gunshot

Other Projected Blood Patterns Arterial Spurts (Vertical and Horizontal) Bloodstain pattern from blood spurt under pressure from a cut artery

Other Projected Blood Patterns Cast-off Blood released or thrown from a blood-soaked object in motion

Three overhead swings with hatchet

Area of Convergence and Area of Origin Determination

Blood Spatter 2 Dimensional Analysis POINT OF CONVERGENCE AND ORIGIN DETERMINATION 2 Dimensional Analysis

Blood Spatter DIRECTIONALITY OF BLOODSTAINS When a droplet of blood strikes a surface perpendicular (90 degrees) the resulting bloodstain will be circular.   Blood that strikes  a  surface at an angle  less than  90 degrees will be elongated or have a tear drop shape. Directionality is usually obvious as the pointed end of the bloodstain ( tail ) will always point in the direction of travel.

IMPACT ANGLE DETERMINATION ANGLE of IMPACT is the acute angle formed between the direction of the blood drop and the plane of the surface it strikes By utilizing trigonometric functions its possible to determine the impact angle for any given blood droplet. SIN θ = opp  (a)               hyp  (c)

Blood Spatter SIN θ = Width (a) 1.5cm Length (c) 3.0cm ArcSIN of 0.5= 30 Degrees (blood drop came from 30 Degrees out)

Blood Spatter-Direction of flow Blood traveled from left to right

5 mL blood squirted from a syringe from a height of 1 m Splash 3

Blood Spatter-Origin of Blood

Blood Spatter 3 Dimensional Analysis POINT OF CONVERGENCE AND ORIGIN DETERMINATION 3 Dimensional Analysis

Blood Spatter-Origin of Blood Convergence

Blood dries in a timed fashion and this may help determine time of crime

Factors that effect drying time Volume Surface Texture Porosity Environment Temp Humidity Air circulation

What information can you get from bloodstain patterns? Mechanism of bloodstain pattern formation Position of people or objects Movement of people or objects Sequencing events