Forensics blood unit

Red blood cells

They are the cells in blood that carry oxygen from the lungs to the body tissues and return carbon dioxide to be exhaled. Most abundant.

White blood cells

They are the cells in blood that are part of the immune system, defending the body against infections and foreign substances.

Plasma

The liquid component of blood that carries cells, nutrients, hormones, and waste products throughout the body. It makes up about 55% of total blood volume.

Platelets

Small cell fragments in blood that help with clotting and prevent bleeding.

Serum

The clear fluid that remains after blood has clotted and the cells and clotting factors have been removed. It contains electrolytes, antibodies, antigens, and other substances.

Agglutinogens

substances on the surface of red blood cells that determine blood types and can trigger an immune response if mismatched.

Antigens

molecules that the immune system recognizes as foreign or self, playing a key role in immune responses and blood type classification.

Antibodies

proteins produced by the immune system in response to antigens, capable of binding to and neutralizing foreign substances like pathogens or mismatched blood.

Agglutination

the clumping of red blood cells caused by the interaction between agglutinogens and antibodies, often used in blood typing and transfusion reactions.

Type A blood

is characterized by the presence of A antigens on the surface of red blood cells and is associated with Type a antibodies in the plasma. Can give blood to A and AB blood types. Can receive blood from O and A.

Type B blood

is characterized by the presence of B antigens on the surface of red blood cells and is associated with Type A antibodies in the plasma. Can give blood to B and AB blood types, and can receive blood from O and B.

Type AB blood

is characterized by the presence of both A and B antigens on the surface of red blood cells, with no antibodies for A or B in the plasma. It can give blood to AB only, but can receive from all blood types.

Type O blood

is characterized by the absence of A and B antigens on the surface of red blood cells, but has both A and B antibodies in the plasma. It can give blood to all blood types but can only receive from O.

Kastle-Meyer

is a color test for detecting blood, primarily based on the oxidation of phenolphthalein by hemoglobin. It results in a bright pink color when blood is present.

Hemastix

are test strips used to detect the presence of blood in urine or other samples. They change color in the presence of hemoglobin. Changes to a yellow-green color

Luminol

is a chemical used in forensic investigations to detect trace amounts of blood at crime scenes. It emits a blue light when it reacts with hemoglobin.

Fluorescein

is a fluorescent dye used in forensics to visualize blood stains at crime scenes. It fluoresces bright green when exposed to certain light wavelengths, indicating the presence of blood.

Leuco Crystal Violet (LCV)

is a chemical reagent used in forensics to enhance the visibility of blood stains at crime scenes. It produces a purple color when it reacts with hemoglobin, making it easier to document and analyze blood evidence.

Spatter

refers to the spray or droplets of blood produced when a force is applied to a source of blood, often seen in violent crime scenes. Blood spatter analysis helps reconstruct the events of the crime.

Area of convergence

is a calculation used in blood spatter analysis to determine the location of the blood source by tracing the blood droplets back to their origin on a two-dimensional plane.

Origin/source

is the specific location where the blood was initially deposited or released, important for understanding the dynamics of a violent incident in blood spatter analysis.

Angle of impact

is the angle at which a blood droplet strikes a surface, influencing the size and shape of the spatter pattern in blood analysis.

Parent drop

is the original blood droplet that produces smaller satellite droplets upon impact with a surface, playing a key role in analyzing blood spatter patterns.

Satellite spatter

are the smaller droplets that are distributed around a parent drop after it strikes a surface, providing insights into the direction and force of the impact in blood spatter analysis.

Spines

are elongated extensions of a blood droplet that radiate away from the parent drop upon impact, indicating the direction of force and helping to reconstruct the scene of a blood spatter.

Passive bloodstains

are bloodstains that result from the force of gravity acting on the blood, such as drops or pools, which can provide information about the position and movement of a victim or assailant.

Projected bloodstains

are bloodstains created when blood is propelled by a force other than gravity, such as a beating heart or a weapon, which can offer insights into the dynamics of a violent incident.

Transfer/Contact bloodstains

are bloodstains created when a blood-bearing object comes into contact with a surface, leaving a pattern that can indicate the type of object and movement involved in the scene.

Arterial Gushing

refers to bloodstains that occur when blood is expelled from a cut artery, often resulting in a spurt or spray pattern. This type of bloodstain can indicate the location and severity of an injury.

Cast off patterns

are bloodstains that result from blood being flung from a weapon, which can show the direction and number of swings made during a violent event.

Flow patterns

are bloodstains created by the movement of blood under the influence of gravity, often indicating the position of the victim and the movement during the event.

Swipe patterns

are bloodstains created when an object or person comes into contact with a surface after having blood on it, often indicating the direction of movement in a scene.

Wipe patterns

are bloodstains created when a surface moves through or comes into contact with wet blood, often indicating the motion of the object.

High velocity spatter patterns

are bloodstains created when blood is expelled at a high speed, typically from a gunshot or explosion, resulting in fine droplets that can indicate the origin and mechanism of the injury.

Medium velocity spatter patterns

are bloodstains created when blood is expelled at a moderate speed, often resulting from blunt force trauma, which can help determine the force and angle of the impact.

Low velocity spatter patterns

are bloodstains created when blood is expelled at a low speed, typically resulting in larger droplets that can indicate the directionality and source of the blood.

Running vs. walking

refers to the differences in blood spatter patterns created when a person is running or walking, with running typically resulting in more dispersed and finer splatter patterns due to increased velocity.

Standing still

refers to the blood spatter patterns that occur when a person is stationary, often resulting in more concentrated and larger droplets, indicating minimal movement during blood expulsion.