Blood History

• Different blood types were recognized in 1875, but it wasn't until 1901 that Karl Landsteiner named and standardized the groups.

• In 1940, Landsteiner also discovered the rhesus factor in blood, labeling it Rh+ if the antigen was present in the red blood cells and Rh- if not. 

• Today, blood typing also includes different types of enzymes and proteins that perform specific activities in the body, which helps to individualize the blood.  (More than 150 serum proteins and 250 cellular enzymes have been isolated, as well as many more antigens

What is in Blood?

• The three types of cellular elements in the blood are: erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.

• Plasma is the other portion that is in blood.

What is in Blood

• The plasma is the liquid part of the blood, which is 90% water. The other 10% contains proteins, waste products, gases, and nutrients.

• Plasma makes up 55% of blood.

Blood Volume

• On average, accounts for 8 % of total body weight- 5 to 6 liters of blood for males – 4 to 5 liters of blood for females

• A 40 percent blood volume 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

Red Blood Cells

• Red Blood Cells transport oxygen on molecules called Hemoglobin.

• Erythropoiesis is the production of new red cells.

• They are made at 2-3 million a second.

• Average lifespan is 120 days.

White Blood Cells

• Leukocytes are the mobile units of the body’s immune system. They are also called white blood cells.

• They defend against the invasion of pathogens.

• They identify cancer cells.

• They remove the body’s litter by phagocytosis.

• They can leave the circulation and go to the sites of invasion and tissue damage.

• There are five kinds of leukocytes.

• 5-10 million/ml of blood normal.

Platelets

• They remain functional for about 10 days.

• 1/3 stored in spleen• 250 million/ml of

blood• They begin the

clotting to a wound.

Blood Typing

• Red blood cells carry a substance called an antigen, which produces antibodies to fight infection, and several different types.

• Types of A, B, O. This is based on which antigen is present and which is absent.

Blood Typing

• RH factor is an antigen on blood that may or may not be on the red blood cell. It is labeled as + or -.

• Rare blood types exist in addition to the basic ABO system.

Blood Types and Race

• The "O" type is most common among indigenous people (like Aborigines and Native Americans) and Latin Americans. 

• The "A" type is most common among Caucasians and those of European descent.

• The "B" type is most common among African-Americans and certain Asians (e.g. Thai).  The "AB" type is most common among the Japanese and certain Asians (e.g. Chinese). 

• An interesting phenomenon is that Middle Easterners are somewhat likely to have nucleated red blood cells, whereas normally, red blood cells contain no nucleus .

Blood Forensics• Determination of the type and characteristics of

blood, blood testing, bloodstain examination, and preparation of testimony or presentations at trial are the main job functions of a forensic serologist, who also analyzes semen, saliva, other body fluids and may or may not be involved with DNA typing.

• Blood is the most common, well-known, and perhaps most important evidence in the world of criminal justice today.

• There's no substitute for it, whether for medical or forensic purposes. Its presence always links suspect and victim to one another and the scene of violence. 

Blood Presence Determination

• The first test is simply the use of a powerful light moved across every surface of a crime scene.  That yields possible traces for visual inspection.

• If nothing is seen, but there is reason to suspect blood had been present, a chemical called luminol is sprayed across the scene because it reacts to blood by making it luminescent.  It only takes about five seconds.

• There is one problem with this test: luminol can destroy the properties of the blood that investigators need for further testing.

• The Kastle-Meyer Color Test uses a solution of phenolphthalein and hydrogen peroxide on a piece of filter paper, and when blood of any quantity is present, it turns pink

Blood in the Courtroom

• Bloodstain patterns tell a lot about position and movement during the crime, who struck whom first, in what manner, and how many times.

• This destroys most alibi and self-defense arguments for crime, and at the very least, trips most suspects up in their explanation of what happened.

Blood Forensics

• When a darkish substance is found at a crime scene, it must first be determined to be blood.

• There are several tests—presumptive tests used strictly for screening---that will differentiate between blood and other substances

Animal versus Human

• Investigators use the precipitin test to determine whether the blood is of animal or human origin. In summary, rabbit serum is combined with the sample and if there is a reaction then it is human blood.

• Animals have different antigens than humans do.

Blood Forensics

• After determining that the blood is human, analysts can go ahead and determine blood type with an ABO test, and then work on the gender of the person from whom the blood came.

• These days, thanks to discoveries in 1985, DNA technology has replaced the tests for specific enzymes and proteins. 

• It's more accurate to match DNA from a blood sample at a crime scene to a source than to draw up an entire blood profile

Blood Loss History• Blood may be dripped out, sprayed from an artery, oozed out

through a large wound, or flung off a weapon raised to strike another blow. 

In the 1930s, Scottish pathologist John Glaister classified blood splashes into six distinct types:

• Drops on a horizontal surface • Splashes, from blood flying through the air and hitting a surface at

an angle • Pools around the body, which can show if it's been dragged • Spurts from a major artery or vein • Smears left by movement of a bleeding person • Trails, either in form of smears when a bleeding body is dragged,

or in droplets when it is carried

Blood Pattern Forensics• Blood pattern analysis plays an important role in the

reconstruction of many crime scenes.• The various types of bloodstains indicate how the blood was

projected from the body via several factors: • Type of injuries • The order in which the wounds were received • Whose blood is present • The type of weapon that caused the injuries • Whether the victim was in motion or lying still when the injury was

inflicted • Whether the victim was moved after the injury was inflicted • How far the blood drops fell before hitting the surface where they

were found.

Blood Drop Forensics• The shape of a blood drop can reveal a lot about the conditions in which

it fell.• Examples:• If blood falls a short distance--around twelve inches—at a 45-degree

angle, the marks tend to be circular.  • If blood drops fall several feet straight down, the edges may become

crenellated, and the farther the distance from the source to the surface, the more pronounced the crenellation. 

• A height of six feet or more can produce small spurts that radiate out from the main drop. 

• If there are many drops less than an eighth of an inch across, with no larger drop, then it may be concluded that the blood spatter probably resulted from an impact.

• If the source was in motion when the blood leaked or spurted, or if the drops flew through the air and hit an angled surface, the drops generally look like stretched-out exclamation marks.  The end of the stain that has the smallest size blob indicates the direction in which the source was moving. 

Surface Tension

• The elastic like property of the surface of the liquid that makes it tend to contract, caused by the forces of attraction between the molecules of the liquid.The cohesive forces tend to resist penetration and separation.

Passive Blood Stains

• Passive Bloodstains are drops created or formed by the force of gravity acting alone.

• Types: drips, drops, pools, and clots

Transfer Bloodstains

• A transfer bloodstain is created when a wet, bloody surface comes in contact with a secondary surface.

• Types: smear, wipe, smudges

Projected Blood Stains

• Projected bloodstains are created when an exposed blood source is subjected to an action or force, greater than the force of gravity. (Internally or Externally produced)

• The size, shape, and number of resulting stains will depend, primarily, on the amount of force utilized to strike the blood source.

Types of Projected Blood Stains

• Arterial Spurt

• Cast-off Stains

• Impact Slatter

Impact Angle Determination

• These are found by using math formulas measuring angles. For Example:

• http://nobelprize.org/educational_games/medicine/landsteiner/index.html

• This site is in MHS Science called “Blood Type Game”

• Go there, play the game, take notes on blood typing so you can run tests on the Lois McArthur suspects.